INCH-POUND

MIL-A-12560H(MR)28 November 1990

SUPERSEDING

MIL-A-12560G(MR)15 August 1984

MILITARY sPECIFICATION

ARMOR PLATE , STEEL, WROUGHT, HOMOGENEOUS

(FOR USE IN COMBAT-VEHICLES AND. FOH AMMUNITION TESTING)

This specification is approved for use by the Materials Technology

Laboratory, Department of the Army, and is available for use by allDepartment and Agencies of the Department of Defen$e.

1. SCOPE

1,1 q. This specification covers wrought-steel homogeneous armoc

plate in thicknesses from 1/4 to 6 inches inclusive for use in combat-vehiclesand 1/4 to 12 inches inclueive for use in.proof and acceptance testin9 ofarmoz defeating ammunition (see 6,1 and 6.4.3 ].

1,2 Classification. wrought armor shall be of the following classes asspecified (see 6.1).

1,2,1 class 1. wrought armor plate which iS heat treated tO develOp

maximum resistance. to penetration.

1.2.2 class 2. Wrought armor plate which is heat treated to develop

maximum resistance to shock.

1.2.3 class 3. Wrought armor plate which is heat trea~ed to develop

specific hardness and impact values for evaluation of armor defeatingammunition only. ‘I’hisclass armor is not intended for use in combat-vehicles”.

To meet the thickness tolerances of this class armor special sUrfaCe finishingmay be required.

2. APPLICABLE DOCUMENTS

2.1 Government documents.

2.1.1 Specifications, standards, and handbooks. The following

specifications, standards, and handbooks form a Part of this document to the

extent specified herein. .Unless otherwise. specified, the issues of thesedocuments are those listed in the issue of the Department of Defense Index ofSpecifications and Standards (DODISS) and supplement thereto, cited in the.solicitation (see 6.2).

Beneficial comments (recommendations, additions, deletions) and any pertinentdata which may be of use in improving this “document shOuld be addressed to:

Director, U.S. ArMY Laboratory Command, Materials Technology Laboratory,ATTN : SLCMT-MEE, Watertown, WA U2172-0001 by using the Standardization

Document Improvement Proposal (DD FOrm 1426) appearing at the end of thisdocument or’by letter.

AMSC N/A FSC 9515

DISTRIBUTION STATEMENT A

-. .—

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“f41L-A-12560H(MR)

STANDARDS

MILITARY

MIL-sTD-367 -MIL-STD-41O -

Armor Test Data ReportingNondestructive Testincl Personnel Qualification andCertification

(Unless otherwise indicated, copies of federal and militaryspecifications, standards, and handbooks are available from ,the

Standardization Documents Order Desk, Sldg. 4D, 700 Robbins Avenue,Philadelphia, PA 19111-5094. )

2.1.2 Other Government documents, drawings, and publications. The

following other Government documents, drawings, and publications form a partof this document to the extent specified herein. Unless otherwise specified,

tbe issues are those cited in tbe solicitation.

USATECO14 TOP 2-2-710 - Ballistic Tests of Armor MaterialsQSTAG 335 - Certification of Personnel for Ultrasonic Inspection

(Application fOK cOPieS should be addressed to the Director, DefenseTechnical Information Center, ATTN: DDR, Cameron Station, Alexandria, VA22314 )

2.2 Non-Government publications. The following documents fOKm a part of

this specification to the extent specified herein. Unless otherwise

specified, the issues of the documents wbicb are DoD adopted are those listedin the issue of the DODISS cited in the elicitation. Unless otherwisespecified, tbe issues of documents not listed in the DODISS are the issues ofthe documents cited in the solicitation (see 6.2) .

AMERICAN SOCIETY FOR TESTING AND MATERIALS (ASTM)

ASTM A578 - Straight-Seam Ultrasonic Examination of Plain and Clad CarbonSteel Plates for Special Application

ASTM A751 - Methods, Practices, and Definitions fOK Chemical Analysis of

Steel Products

ASTM E1O - Srinell Hardness of Metallic MaterialsASTM E18 - Rockwell Hardness and Rockwell Superficial Hardness of

Metallic MaterialsASTM E23 - Notched Bar ImDact Testinq of Metallic MaterialsASTM E11O - Test Method fo> Indentati&r Hardness of Metallic Materials by

Portable Hardness Testers under ASTM E23 - Notched Sar Impace

Testing of Metallic Materials

(Application for copies should be addressed to the American Society forTesting and Materials, 1916 Race Street, Philadelphia, PA 19103. )

(Tachnical aOCietY and technical association specifications and standardsare generally available for reference from libraries. They are also

distributed among technical groups and using Federal agencies. )

2.3 order Df precedence, In the event of a conflict between the text of

this document and the references cited herein, the text of this document takesprecedence. Nothing in this document, however, supersedes applicable laws and

regu~ationsunless a specific exempti On has been ~bta!ned:,

2

MIL-A-12560H(wR)

3. REQUIREMENTS

3.1 First article. When specified in the’contract or purchase order (see”

4.2.1.1.2, 6.2, 6.9 and 6.11), a sample or samples of the specified item shall

be.made available to the contracting officer or his authOKized representativefor approval in accordance with 4.2.1.1. The approval of the first article

samples authorizes the commencement of shipment but does not relieve thesupplier of responsibility for compliance with all applicable provisions ofthis specification. The.first article samples and test plates shall bemanufactured by the process proposed for use on production armor. The

manufacturer’s declared chemical analysis must be submitted to the contractingagency and to the ballistic test agency. The ballistic test agency will

record tbe first article ballistic test plates submitted, showing the datestasted.

3.1.1 First time producer, First time producers wishing to qualifY to

this specification should follow the instructions of 6.8.

3.2 Acceptance requirements.

3.2.1 Materials.

3.2,1.1 Structure. Processes of manufacture shall be such as to producesteel plate having, as nearly as practicable, a homogeneous structurethroughout.

3.2.2 Chemical composition. The product analysis of all plates. within aheat shall conform to tbe requirements .of table I unless otherwise negotiatedbetween the steel supplier and the contractor (see 6.12) . All limits asspecified in table I (including any deviations negotiated) shall be submittedin advance to the procuring activity. The contractor may establish and submit

separate limits for each thickness of plate to be furnished (see 6.5). A

statement showing the Product analysis Of each melt and cOmPlete details of.the heat” treatment of each lot shall be furnished for the files of the

procuring activity at no cost to the procuring activity. All elements ofchemical composition shall be shown. in the statement. The chemical

composition range established by tbe producer and the chemical analysis of thematerial submitted shall be reported in accordance with MIL-STD-367, (see6.2.2 and 6.7. )

3,2.3 Heat treatment. All plates in each lot, including sample6, shall

receive the same heat tceatment except for such variations in temperingtemperature as may be necessary to produce the prescribed hardness. The

austenitizing temperature for production plates may varY within a ran9e Of

50° above the temperature used for test plates, but in no case shall itexceed 17000F (see 6.13) .

3.2.4 Processing controls.

3.2.4.1 Heating. Stress relieving the plates, local or gi?neral, shall beallowed after final quenching and tempering. at a maximum temperature of 500Fbelow the tempering temperature. Plates shall not be ‘stress relieved in atemperature range of 600-800°F. After stress relieving, the plates shall betested for hardness and shall meet the requirements of table II.

““3

NIL-A-12560 H(MR)

TABLE I. Chemical composition (product analysis). ~1

MAXIMUM MAXIMUM

RANGE LIMIT

ELEMENT PERCENT PERCENT

cARBON 0,10 0,30 up to 2“ thick, incl.

0.33 over 2“ up to 4“0.35 over 4“

MANGANESE :Up to 1.00% incl. 0.30 -.

Over 1.00% 0.40 --

PHOSPHORUS -- 0.025

sULFER -- O,(I15

SILICON:--

Up to 0.60% incl. 0,20

Over 0.60% to 1.00% incl. 0.30 --

Over 1.00% 0.40 --

NICKEL 0.50 _-

CHROMIUM:Up to 1,25% incl. 0.30 --

Ovec 1.25% 0.4U --

MOLYBDENUM :Up to 0.2U% incl. 0.07 --

Over U.20% 0.15 --

VANAD IUt4: 0.10 --

BORON -- -- y

COPPER -- 0.25 ~/

TITANIUM -- 0.10 y

zIRCONIUM .- 0.10 y

ALUMINUM --

LEAD

0,10 y-- 0.01

TIN -- 0.02 y

ANTIMONY -- 0,02 y

ARSENIC -- 0.02 y

&/ This table lists the maximum range for elements of the manufacturer’s

established chemical composition.

~/ When the amount of boron is specified in the alloy, its content so

determined by heat analysis shall not exceed 0.003 percant.

L33When the amount of an element i6 less than 0.02 percent the analysis may be

reported as 0.02 percent+

4

~

MIL-A-12560H[MR)

I3.2.4.2 Repairing. Unless otherwise approved by the procuring activity,

weld repairs shall not be made on any plates.

3.2.4.3 Forming. Forming after the final quenching and temperingoperations shall not be done except when authorized by the procuri%lg activity.

3.2.4.4 Grinding. Grinding is not ~equi~ed but maY be perfOrmed tOremove minor defects not affecting the serviceability” of the material provided

that,’unless otherwise authorized by the procuring activity, the grinding doesnot result in the reduction of the plate thickness in tbe ground aKea to less

than the tolerances specified in tables III, IV, or V as applicable.

3.2.5 Mechanical properties.

3.2.5.1 surface hardness. The average surface hardness of each plate

including first article samples shall be within tbe SB range shown in table 11

for the applicable class and thickness. . The diameters of Brinell hardnessimpressions on any individual plate “shall not vary by more than 0.15 mm.’

3.2.5.2 u. Tbe Charpy V-notch impact test results of armor platesubmitted shall meet the requirements shown in table VI for the applicable

hardness and thickness. The Charpy V-notch impact specimens shall be obtained

in botb the TL orientation (i.e., transverse to the major direcbion of rollingwith the notch perpendicular to the plate surface so that tbe crack willpropagate in the longitudinal direction) and the LT orientation “(i.e.,parallel to the major direction of Lolling).

3.2.5.3 Bend test. When specified in the contract or order a bend testshall be performed. Bend test criteria shall be agreed upon by tbe supplierand fabricator.

3.2.6 Ballistic requirements. Ballistic requirements for class 1 andclass 3 wrought homogeneous armor shall be in accordance with the Appendixof this specification. class 2 armor shall not be subject to ballistic testrequirements.

3.2.7 Dimensions and tolerances.

3.2.7.1 Dimensions. Classes 1 and 2 armor plate shall. comply with tbedimensions and tolerances specified on applicable drawings or in the contract

(see 6.2). Class 3 armor tolerances on length and width dimensions shall beplug 1 1/2 inches and minus zero.

3.2.7.2 Thickness.

3.2.7 .2.1 Thickness Measurements (ClaSS 1 and ClaSS 2 “AKMOK). Three

thickness measurements will be taken along each side of the length of eachplate (one near each end and one in the middle) and two thickness measurementswill be taken on each end (about 1/3 of the distance from each edge) for a

total of 10 measurements. Measurements will be made in accordance with4.5..2. The acceptance of each plate will be based on these measurementsmeeting the thickness requirements set forth in table III or IV as applicable.

5

MIL-A-12560H(MR)

TABLE 11, Hardness requirements.

Brinell Brinell

Specified nominal hardness indentation Rockwell C

thickness of plate Armor range (BHN) diameters hardness (HNC)

(inches) class (3000-Kq load) (millimeters) range~ To and

i-nq

0.250 0.499 l&3 341-3ss 3.30-3.10

0.500 0,749 l&3

36.6-41.8331-375

0.7503.35-3.15

1.249 l&335.4-40.5

321-375 3.40-3.15 34.3-40.51.250 1.990 l&3 293-331 3.55-3.352.000 3.990 163

30.9-35.4269-311 3.70-3.45 27 .7-33.0

4.000 6.000 l&3 241-277 3,90-3,65 22.7-28.7

6.001 6.999 3 241-277 3.90-3,65 22,7-28.7

7.000 8.999 3 223-262 4.05-3,75 19,2-26.7

9.000 12.000 3 212-248 4.15-3.85 16.4-24.20.250 1,250 2 277-321 3.65-3,40 28,7-34.3

3.2.7 .2.2 Thickness Measurements (Class 3 Armor). The thickness of all

Class 3 plates shall be determined by measurements made one foot on centersover the entire surface of each plate. The measurements will be to theneatest thousarrdtb of an inch. The acceptance of each plate will be based onthese measurements meeting tbe thickness requirements of table v for Class 3armor,

3.2.7 .2.3 Thickness Tolerances. The thickness tolerances of each plate,after final treatment, shall be in accordance with tables XII and IV forClasses 1 and 2 armor or with table V fOr Class 3 armor.

3.2. 7.3 FldtneSS. Unless otherwise specified in the contract or order,

(see 6.2) the flatness tolerance of each plate shall be within therequirements specified in table VII. Tighter tolerance requirements may bespecified in the contract or order and shall be as agreed upon between thecontractor and the procuring activity.

3.2.7.4 Waviness. Unless otherwise specified in the contract or order,(see 6.2) the waviness tolerance of each plate shall be within tberequirements of table VIII for the applicable. thickness.

3.2.8 Identification marking. Identification marking and records shallbe such as to ensure positive identification of all plates, including testsamples and specimens, with the lot and corresponding heat fIom which theywere produced. First article and acceptance ballistic test plates shall alSO

be marked with the manufacturer ‘a name or trademark, the number of thisspecification; and tbe ordered plate thickness in inches. First azticleplates shall be marked ‘PRE”, acceptance plates ‘ACCW and retest plates will

be marked “RI” and ‘R2*. If a second set of retest plates are submitted theyshall be marked “RR1” and ‘RR2n. Tbe marking shall be approximately 1/16 inch

deep and approximately 1/2 inch high and located along the edge with the

lifting hole, if present, and shall be stamped into tbe surface unless the

6

MIL-A-12560H(MR)

plate hardness makes painting necessary: All plate markings shall be

highlighted with a highly visible yellow or orange border such as fluorescentpaint or highlighted with a special white paint intended to delineate and

highlight stamping. The primary plate rolling direction shall be identified.

Manufacturers supplying armor to be used for proving ground testing of

ammunition are required to:

a. Mark each class 3 plate with one foot square blocks showing thickness

at the center of each block. The acceptance of each plate will be based onthese measurements meeting the thickness requirements set forth in table V.

b. stamp each plate ‘HOMO, CLASS 3, MIL-A-12560, plate No. _, heat

No,._. m Stamping shall be approximately 1/2 inch bigb letters to a depth

approximately 1/16 i.ncb. Location of stamping for all plates will be in tbeupper right hand corner.

3.2.9 Information required. A statement showing the product analYSiS 0<

each melt and complete details of the heat treatment of each lot shall be

furnished for the files of the procuring activity. All elements of thechemical composition ehall be shown in the statement, including special

additives or hardening agents, whether shown in table I or not.

3.2.10 Workmanship.

3.2.10.1 Surface imperfections. Tbe top and bottom surface of each plate

shall be free from the following surface defects: slivers, laps, checks,

seams, blisters, snakes,” cold shuts, cracks, burning, and laminations (see6.4). The surface of each plate shall be such that mill scale or oxidation

product shall not. interfere with determination of acceptability.Imperfections listed above which are of such a nature as to affeCt thefabrication of the material, are rejectable.

3.2.10 .1.1 Depth of imperfections. ‘lbe depth of rolled-in scale, scalepitting, mechanical gouges, or snakes shall not exceed 0.015 inch.and shall

not reduce tbe steel thickness below the allowable minimum. Isolated

individual pits over 0.015 inch deep but not over 0.03 inch deep and notwithin 6 inches of each other and which do not violate tbe minimum allowable

thickness, as specified in the applicable drawings and fabrication documents,are acceptable.

3.2.10.2 Edqe preparation. Thermal cutting shall be permitted afterfinal heat treatment provided the procedure, which may include grinding afterthermal cutting, is such that no cracks develop on any thermally cut edgewhether detected by nondestructive inspection, or as agreed upon in thecontract. Tbe heat affected zone of thermally cut plates (uP to and inclrrdingl/2-inch in thickness) shall not exceed 152 times the plateS thickness froio

the cut edge. FrJrplates OVeI. l/2-inch thick, the heat affected zone shall

not exceed 5/8-inch from” tbe cut edge. In order to have the heat affectsdzone exceed these limits approval shall be obtained from the procuring

activity.

7,..,.

idd-+.+-immm”m mmcnmmrnm.nm. wmcom. kaImmmmmmmmwe -*-3*mmnmwnww w.wt. b;~ooooooooo 000.000000 Ooyo aa. . . . . . . . . . . . . . . . . . . . . .!.

8

~

MIL-A-12560H(MR)

TABLE IV, Thickness tolerances for Class 1 armor plates over 2“ thick.

~Thickness tolerances in inches over and under ordered thickness for single plateover 2 inches in thickness when ordered to thickness in inches.

Specified Tolerances over and under specified thickness for widthe qiventhickness Under 60’ 60” to S4” 84” tO 120” 120’ to 132m 132” and

inches excl. excl. excl, excl. over

IFrom ~—

1“ 2 - 4, excl. L/ .060 .068 .06B .076

4 - 6, incl. ~/ .076 .076 .083 .091

6- S, incl. ~/ .091 .091 .098 .107

8 - 10, incl. ~/ .107 .107 .122 .138

10 - 12, incl. ~/ ,13s .138 .144 .160

I

~~ When plates

tolerances shallunder 60” are rolled double width, the equivalent wider plate

apply .

TABLE V. Thickness tolerances for ClaSS 3armor plate,~/

Permissible variation

Specified plate thickness plus nr minus(Inches) (Inches)

g To and includinq

0.250 0.500 0.015

0.500 1.125 .0201.125 1.499 .025

‘ 1.499 1.749 .030

1.749 1.999. .0351.999 2.999 .040

2.999 4.000 .045

4.000 6.0006.000

.0758.000 .0s3

8.000 10.000 .098 ““10.000 12.000 .122

~[ This armnr is not intended for use in combat vehiclds.To obtain these thickness tolerances special surfacingfinishing may be required.

MIL-A-12560H(MR)

TABLE VI. MiniMUM charpy v-notch impact requirements

(at -40°F. + 20F) ~/

Brinell Plate Minimum impact values

hardneas (BHN) thickness (avera9e of two or moreaveraqe (inches) test specimens), ft. lbs.

Specimen Size

Standard 3/4 width 1/2 width

207

212217

223229235

241

248255

262269277285

262269

277285293302311321331341352363375388

4-12 incl.m.

.“.

n

.

““

.

.

1/4 to lessthan 4....“

.

“

.

.

.

“

.

65

6361

595755

53

5047

44403733555147 36 2443 33 2239 30 2035 27 1831 24 1628 21 14

25 19 13

22 17 1119 15 10

17 13 9

16 12 816 12 8

~/ ASTM E140 shall be UBed to convert HRC readings to HS equivalents.

10

I

MIL-A-12560 H(MR)

TABLE VI 1. Permissible variations for flatness, in.

~Specified Variations from a flat surface for specified widths, in.thickness, i!. Under 48 to 60 to 72 to 84 to 96 to

48 60 excl. 72 excl. 84 excl. 96 excl. 108 excl.

1/4 to 3/8 excl. 3/4

3/8 to 1/2 e%cl. 1/21/2 to 3/4 excl. 1/23/4 to 1-1/4 excl. 1/21-1/4 to 1-5/8 excl. 3/81-5/8 to 3 excl. 3/83 to 4 excl. 3/84 to 6 excl. 1/2

6 to 8 excl. 9/168 to 10 excl. 5/8

10 to 12 excl. 11/16

15/169/169/169/161/23/81/2

5/811/163/4

13/16

1-1/85/85/85/81/27/161;25/8

11/163/4

13/16

1-3/4

3/4

3/43/45/81/25/8

3/413/167/8

15;16

1-7/87/8

7/87/83/45/83/4

7/815/161

1-1/8

3/43/4

7/815/161

1-1/8

NOTE : The above variations apply to plates up to 12 feet in length, or to any12 feet or longer plates.

3.2.10.3 Edge condition. Plate, edge on plates delivered after heattreatment shall be free of cracks. The supplier shall PraCtiCe such necessarYprocess controls to prevent this condition.

3.2.10.4 Internal soundness. All plates l/2-inch and greater in thicknessshall be ultrasonically examined for internal soundness in accordance with4.6.5, The steel supplier shall institute process Controls such that any edgeof any cut part shall comply with the requirements of 3.2.10.4.1.

3.2 ,10.4.1 Acceptance criteria.

3.2.10 .4.1.1 Single linear indications. In any four inches of length a

single linear indication shall not exceed twice the plate thickness.

3 ,2.10.4.1.2 Multiple linear indications. Multiple linear indicationsshall not,exceed 1-1/2 times the plate thickness’ if,two or more lie in the same

plane. The total length of indications in one plane, in any four inch length,shall not exceed twice the plate thickness. No more than ten indications,

whether in one plane or ‘multiple planes, are permitted in any four inch length.

3.2.10 .4.1.3 _. All cracks are rejectable.

3.2.10 .4.1;4 Removal of large indications. Large indications shall bere”moved by the manufacturer nr processor by grinding, provided the resultingcavity does not exceed l/4-inch.

11

MIL-A-12560HIMR)

TABLE VIII. Waviness tolerances for Plates.

Flatnesstolerance When number of waves in 12 ft is:

from 1 2 3 4 5 6 7

table VII

5/163/87/16

1/29/165;B

11/163/413/167/8

15/1611-1/8

1-1/41-3/8

1-1/21-5/81-3/41-7/822-1/82-1/42-3/82-1/22-5/82-3/4

5/16

3/87/16

1/2

9/165/8

11/163/413/16

7/8

15/1611-1/B

1-1/41-3/8

1-1/21-5/81-3/4l-7/822-1/82-1/42-3/82-1/22-5/82-3/4

l/45/165/16

3/8

7/161/21/29/165/8

11/16

11/163/47/8

15/161-1/16

1-1/81-1/41-5/161-7/161-1/21-5/81-11/161-13/16l-7/B22-1/16

3/163/161/45/16

5/163/83/87/167/16

1/21/29/165/8

11/163/4

7/B15/1611-1/161-1/81-3/161-1/41-5/161-7/161-1/21-9/16

1/83/163/163/161/4l/45/165/165/16

3/83/87/161/2

1/29/165/811/163/413/167/8?/815/1611-1/161-1/81-1/8

1/8

1/81/83/163/163/163/161/41/4

i/45/165/163/8

3/87/161/21/29/169/16

5/811/1611/163/413/1613/167/8

1/161/161/8

1/81/81/8

3/163/163/163/16

1/41/41/4

5/165/163/83/87/167/161/21/29/169/169/16

5/B5/8

1/161/161/16

1/16l/B1/81/81/8i/81/8

3/163/163/161/41/41/4

5/165/165/163/83/83/87/167/167/16U 2

NoTE 1. Waviness denotes the deviation of the top or bottom surface from ahorizontal line, when the plate is resting on a flat surface, as measured inan increment of.less than 12 ft of length. Tbe waviness tolerance is a

function of tbe flatness tolerance as obtained from table VII.

NOTE 2, When the flatneSs tolerance is l/2-inch or less for plates l/2-inchor less in thickness, the waviness tolerance shall not apply.

12

‘MIL-A-12560H(MR)

4. QUALITY ASSURANCE PROVISIONS

4.1 Responsibility for inspection. Unless otherwise ‘specified in the

contract or purchase order, the contractor is responsible fo~ the performance

of all inspection requirements (examinations and tests ) as specified herein.

Except as otherwise specified in the contract or purchase order, thecontractor may use his own or any other facilities suitable for theperformance of the inspection requirements specified herein, unlessdisapproved by the Government. The Government reserves the right to performany of tbe inspections set forth in this specification where such inspectionsare deemed necessary to ensure supplies and services. conform to prescribedrequirements.

4.1.1 Responsibility for compliance. All items shall meet all

requirements of sections 3 and 5. The inspection set forth in thisspecification shall become a part of the co,ntractoc’s overall inspectionsystem or quality program. .The absence of any inspectio? requirements in tbespecification shall not relieve the contractor of the responsibility ofensuring that all products or supplies submitted to the Government for

acceptance comply with all requirements of the contract. Sampling inspection,

as part of manufacturing operations, is an acceptable practice to ascectainconformance Eo requirements, however, this does not authorize submission of

known defective material, eitber indicated or actual, nor does it commit tbeGovernment to accept defective material.

4.2 classification,

4.2.1 Classification of inspection. Tbe inspection requirements

specified herein are classified as follows:

a. First article inspection.b. QualitY cOnfOrmance in?PectiOn (acceptance) ?

4.2.1.1 First article inspection. When required, the first article

samples submitted in accordance with 3.1, shall be examined for ail theprovisions of this specification applicable to end item examination.

4.2.1 .1.1 First article tests. First article tests (see 6.2) shall consist

of all the tests specified in 4.6.

4.2.1,1.2 First article ballistic test. Unless otherwise specified (see

3.1, 6;2, and 6.11), the first article ballistic test shall not be requiredprovided (a) the manufacturer, within 37 months, has produced acceptableplatee within the sama nominal thickness ranges of table IX, and (b) his

production conditions are the same as’for previously accepted plates. Asupplier wbo has previously met the first article requirements w“ill furnish

tbe procuring activity the firing record of the ballistic test plate abd otherpertinent data relative to complaince with first article. Neither firstarticle nor acceptance ballistic tests will be required for plates ordered to’thicknesses of mor,e than 6.25 inches. Acceptance of these tbir!ker plates will

be based on meeting the other requirements of the specification.

13

MIL-A-12560H(MR)

4.2.1,2 Quality conformance (acceptance) inspection. The acceptance

examination under 4.5 and the tests under 4.6 shall serve as a basis for theacceptance of individual production lots.

4,3 Lot. A lot shall consist of all production and ballistic test plates—of the same melt of steel, of the same thickness, having the mme treatment,and heat-treated with the same thermal cycle in the same productionfurnace in the seinefacility. When Specified by the procuring activity(see 4.3.1), production and ballistic test plates may be allowed to beheat-treated separately. The test plate shall be heat-treated in a production

furnace.

4,3.1 Separately heat treated ballistic test plate. When the procuringactivity allows a ballistic test plate to be heat-treated separately from theproduction plates it represents, (see 6.2) it will be so stated in the data tobe supplied in accordance with MIL-STD-367 (see 6.13).

4.4 SamplinQ.

4.4,1 First article sampling.

4.4.1.1 Chemical composition. Samples for chemical analysis shall betaken from each plate selected for the ballistic tests.

4.4.1.2 Impact samples. At least one impact test sample Ghan he taken

from each submitted test plate in accordance with 4.6.3.1 or 4.6.3.2 and eachehall consist of enough material for four impact specimens.

4,4.1.3 Ultrasonic examination. Each submitted test plate 3/8 inch in

thickness and thicker, shall be ultrasonically examined in accordance with4.6,5.

4.4.1.4 Ballistic test plates. Three ballistic test plates for each

nOIIIiflalthickness ranoe (see table Ix) shall be randomly selected andsubmittedrepresentbe of the

thicknessagency as

4.4.2

for ballistic test. Any thickness within the range may be chosen to

any other thickness in the range but the three plates submitted mustsame ordered thickness. Unless otherwise sPecified, the average

of each test plate shall be determined at the teat site by the testindicated in 4.4.2.5,

Sampling for quality conformance inspection.

4.4.2.1 For chemical analysis. At least One sample for chemical analysisshall be taken from each heat in accordance with the applicable IIethodspecified in ASTM A751 (Bee 6.6).

4.4,2,2 For hardness test. The Brinell hardness of each plate as heat

treated in each lot up to 1 1/2” thick shall be measured in two places, one ateach end of a diagnal on one plate surface. The Brinell hardness of each

plate as beat-tzeated in each lot over 1 1/2” thick shall be measured in four

places, one at each end of a diagonal on both plate surfaces.

14

MIL-A-12560H(MR)

4.4.2.3 For Charpy V-notch impact tests. At least one sample shall be

taken from a plate representing each lot for Charpy V-notch impact tests. The

sample shall be the same thickness as the plate they represent and largeenough to obtain at least two specimens, in each direction, from each sample

in accordance with 4.6.3.

4.4,2.4 Ultrasonic examination. All plates over 1/2 inch in thickness

shall be examined ultrasonically. Tbe ultrasonic examination shall be

performed in accordance with 4.6.5.

4,4.2.5 For ballistic acceptance SamPleS. Unless otherwise specified in

the contract or order, one test plate shall be submitted from each lot. Tbeminimum plate size shall be as shown in table IX.for the applicablethickness. unless otherwise specified, the average thickness of.each testplate shall be determined at the test site by taking the average of fourthickness measurements. Measurements shall be made at least 1 inch from each

edge but preferably at random in.the intended imPact area. Thickness

measurements for plates .UP to and includin9 2.?50 inch shall be read tO thenearest 0.001 inch. Plates over 2.750 inch shall be read to the nea~est 0.01

inch. If a producer submits plates outside the specified plate tolerances

(see tables III, IV and V) the procuring activity shall be notified. A checklist, Format I of MIL-STD-367 (see 6.7), shall be completed and submitted with

each ballistic test plate.

4.5 Examination.

4.5.1 Visual. All steel plate shall be subject t~.visual inspection forcompliance -he requirements for surface conditions’ (see 3.2.10. 1), edgequality (see 3.2.10.3 and 3.2.10.4) and identification marking (see 3.2.8).

4.5.2 Dimensions. All steel plates shall be subject to inspection for

compliance with dimensional and tolerance requirements (3.2.7 ). Each class 1

and class 2 plate shall be inspected using a calibrated micrometer at threeevenly distributed points 3/8 to 3/4 inches’ in from the longitudinal edge andat two evenly distributed points along each transverse edge. Each class 3

armor plate shall be divided into one foot squares painted on one surface andthe results of each. thickness measurement shall be painted in the square in

which it was taken.

4.5.3 Preparation for shipment. Examination shall be made to determine

compliance with the requirements for preparation for shipment (see section 5 ).

4.6.1 Chemical analysis. Chemical analysis shall be conducted inaccordance with the applicable method specified in ASTM A751 (see 6.6). The

analysis shall comply with the declared composition established in accordance

with the requirement of table I (see 3.2.2).

4.6.2 Hardness tests. Brinell hardness tests shall be conducted in

accordance with either ASTM E1O or ASTM E11O using a 10 mm carbide ball and a3000 kilogram load. surface scale and decarburization shall be removed from

the areas where the tests are to be made. Hardness tests may be made on the

surfaces of pieces cut from the plate after heat treatment.

15

MIL-A-12560H(MR)

TABLE IX. Ballistic test plate sizes and corresponding test projectilesfor first article and acceptance testing.

Nominal thickness Minimum SiZe (a) Of Test projectile

range (iIICheB) test plates (inches) and obliquity

0.25 to 0.565 incl. 12 X 36 Cal .30AP, )42at 0°

0,565 to 1,125 incl. 12 X 36 Cal .50AP, M2 at 0°

1.126 to 2.750 incl. 12 X 36 20-mm APIT, M602 at 0°

2.751 to 3.500 incl, 60 X 60 90-mm APC, M82 at 450

.3.501 to 3.999 incl. 60 X 60 90-mm APC, M82 at 30°

4.000 to 6.250 incl 60 X 60 90-mm AP, M318 at 0°

Over 6.251 (b)

NOTE: (a) Other sizes may be submitted for the convenience of the manufacturerif approved by the ArmOK Vulnerability Divi8ion, USAcs!rA,Aberdeen ProvingGround.

(b) No ballistic test required.

4.6.2.1 Hardness teets on impact test specimens. Except as provided in4,6,2,2, each sample from which impact test specimens are taken shall have ahardness check made upon it as follows: For samples 1/4 to 1/2.inch inclusivethe hardness check shall be made on the surface. For samples of 1/2 inch upto

4 inches in thickness, at least two hardnees tests shall be taken fromanadjacent location, midway between the surfaces of the plate. Fox samples of

4 inches in thickness or greater, at least six hardness tests shall be made atequal intervals across the plate thickness.

4.6.2.2 Rockwell bardnese tests on impact specimens. At the option oftbe contractor at least two Rockwell C hardness tests may be made on eachimpact test specimen sampled from each lot. The test specimens shall beprepared and tested in accordance with ASTM E18. The average shall not exceedthe maximum requirement for thickness specified in table II.

4,6,3 Charpy V-notch impact tests. At leaSt two Charpy V-notch impacttest specimens shall be taken in each direction from each sample as obtained

in accordance with 4.6.3.1 or 4.6.3.2, and shall be prepared and tested in

accordance with ASTM E23.

4.6.3.1 For samples’ less than 4 inches in thickness. Charpy v-notchimpact test specimens from samples less than 4 inches in thickness shall betaken in both tbe TL orientation and in the LT (see 3.2.5.2) orientation from

a location midway between the top and bottom surfacea of the plate and atleast 4 inches or 2T, whichever is less, from any quenched edge as well asoutside the heat affected zone of any thermal-cut edge. When tbe amount of

material available ia insufficient to obtain standard specimens, tbe largest

16

MIL-A-12560H(MR)

attainable subsize

E23 shall be used,

Itable VI.

Charpy V-notch impact specimens shown in figure 4 of ASTM

and the results compared to tbe applicable requirements of

4.6.3.2 For samples 4 inches or greater in thickness. Charpy V-notch

impact test specimens from samples 4 inches or greater in thickness shall betaken from a location such that the centerlines of the specimens are

approximately 1 inch below the surface of the plate and at least 4 inches fromany quenched edge as well as outside the heat-affected zone of any thermally-cut edge.

4.6.4 Ballistic Tests. Ballistic testing of armor plate shall be

conducted at a Government test facility specified in the contract or order “or

at a test facility aPProved by tbe Government. Testing shall be conducted in

accordance with the requirements of the Appendix.

4 .6.5 Ultrasonic examination.

4.6,5.1 Inspection equipment. The ultrasonic soundness inspection

equipment Bhall conform to ASTti A578.

4.6.5.2 Procedure. Unless otherwise specified (see 6.2) the ultrasonic

examination shall be carried out in accordance with ASTM A578 with thefollowing exceptions:

(a) Scanning shall be continuous over 100% of the plate surface.(b) Scanning rate shall be at a speed where recordable discontinuities

can be detected.

(c) The testing frequency shall be a minimum of 2 megahertz (MHz).

(d) AnY area within a plate where a discontinuity produces a ccmti”uoustotal lass of back reflection accompanied by continuous indicationson the same plane that cannot be encompassed within a circle whose

diameter is l-in. shall be cause for rejection of that plate. Alldiscontinuities will be evaluated using a frequency of 2 megahertz

(MHz).

4.6.5.3 Certification of inspection’ personnel. Unless otherwisespecified (see 6.2), personnel performing ultrasonic inspection shall comply

with the qualification requirements of MIL-sTD-41O, level 1, or equivalent, asdetermined by QSTAG 335. Personnel making accept/reject decisions in

accordance with the process described by this specification shall be qualifiedto at least a level II per MIL-sTD-41O or equivalent, as determined by QSTAG335,

4.6.6 Reduced testing. At the discretion of the procuring activity, theamount of testing may be reduced provided the results on consecutive@ lotsindicate that a “satisfactory uniform product meeting the testing requirementsis being produced (see 6,2) . Reduced teeting shall be in accordance with asystem previously approved or established by the procuring activity involved.

1?

MIL-A-12560H(MR)

4.6.7 Rejection and retest.

4.6 ,7.1 Rejection, Unless otherwi8e specified in the contract or order

(see 6.2), failure of the first article samples to meet the requirements ofthis specification shall he cause for rejection of the process, and failure of

the acceptance samples to meet the requirements of this specification shall because for rejection of the lot (see 4.6.7.2).

4.6.7.2 -. Unless a specific retest.procedure is specified in thecontrack or order (see 6.2), two retest samples shall be submitted for eachfailed sample. Failure of either of the retest samples (plates) shall because foc rejection of the material. First article retests shall not bepermitted until the supplier has made the necessary corrections in the

processing of the material to tbe satisfaction of the procuring activity.

4.6.8 Hardness traverse test. Prior to production to assure compliance

to paragraph 3.2.10.2, the size of the heat affected zone for thermally cut

edges shall be determined by takin9 Rockwell c hardness tests at 1/16 inchincrements from the edge. Surface scale and decarburization shall be removedfrom the test surface. The distance at which there is no change in surfacehardness shall be considered the depth of the heat affected zone. Thecontractor ehall document the test results for each thickness and thermalcutting method used in production. The contractor is also responsible fOrdocumenting all heat input controls to assure the cutting process is undercontrol. Re-verification of heat affected zone size for subsequent productionlots is not required provided there is no change in the cutting method or heatinput from that previously tested. Tbe records shall he available for KeVieWby the cognizant government representative.

5, PACKAGING.

5.1 Preservation and packagi”n~. Unless otherwise specified in thecontract or order, preservation and packaging shall be level”C (see 6.2).

5.1.1 Level C. Cleaning, drying, preservation, and packaging shall be in

accordance with manufacturer’s commercial practice.

5,2 Packing. Unless otherwise specified in the contract or order,

packing shall he level C (see 6.2).

5.2.1 Level c. All plates shall be packed for shipment in such a manner‘as to ensure acceptance and safe delivery by tbe carrier for the mode oftransportation employed.

5.3 Markinq. In addition to any special marking specified in thecontract or order, shipments shall be marked in accordance with the

requirements of the cognizant activity.

6. NOTES

(This section contains information of a general or explanatory nature thatmay be helpful, but is not mandatory. )

18

I MIL-A-12560H(MR)

6.1 Intended use. The armor specified herein is intended for use on

combat vehicles and proof and acceptance testing of armor defeating

ammunition. but mav also be applicable to armor for emplacements, shields,

~

pill boxes: testin~,,and the i~ke.

6.1.1 Class 1, Class-1 wrought armorwhere maximum resistance to penetration byis required.

is intended for use in those areasarmor piercing types of ammunition

6.1.2 Class 2. Class-2 wrought armor. is intended for use in those areas

where maxim-stance .to failure under conditions of high rates of shockloading is required and where resistance to penetration by armor piercingammunition is of secondary importance. It is intended for use as protection

against anti-tank land mines,. hand grenades, bursting shells, and otbec blast-producing weapons,

6.1.3 Class 3. Class 3 wrought armor is intended for use in the proof

and acceptance testing of armor defeating ammunition. This class is notintended for.use in combat vehicles. Lift hole requirements for class 3 armor

will be specified by the procuring activity.

6.2 Ordering data. Procurement documents should specify:

6.2.1

a.b.c.d,e.f.

9.

b.

i.

j.

k.1.

m.n.0.

P.

Procurement requirements.

Title, number, and date of this specification.Class of steel.If first article eample is required (see 3.1) ,If local or general heating is permitted (see 3.2.4.1).If weld repairing is permitted (see 3.2.4.1.2).Dimensional IegUirementS (see 3.2.7 ).Name of inspecting agency when inspection shall be performedby other than the contractor (see 4.1) .When a special first article ballistic test is required

(see 3.1, 4.2.1,1.2 and 6.11).If ballistic test plates may be separately heat-treated from theproduction plates it represents, (see 4.,3.1).If ballistic acceptance samples should be other than in4.4.2.5.If ultrasonic examination is to be different than 4.6.5.2.If certification of inspection pereon.nel is different from 4,6.5.3.If rejection and retesting differs from 4.6.7.

Tbe reduced testing plan when applicable (see 4.6.8).Preparation for delivery if different than specified in.section 5.If lifting holes are required (see 6.1.3).

6.2.2 Consideration of data requirements. The following datarequirements should be considered when this specificat.io” is applied on a

contract. The applicable Data Item Descriptions (DID’s) should be reviewed inconjunction with the specific acquisition to ensure that only essential dataare requested/provided and that the DID’s are tailored to reflect the

requirements of the specific acquisition. To ensure correct contractual

aPPlication of the’data SequiZemen!s, a Contract Data Requirements List (DD

~ MIL-A-12560H(MR)

Form” 1423) must be prepared to obtain the data, except where DOD FAR

Supplement 27.475-1 exempts the requirement Ear a DO Form 1423.I

I Suggested

Reference Para. DID Number DID Title Tailorinq

3.1 UDI-T-23790 Report, FiKat Article ---

3.2.9 UDI-T-23264 Certification Data Report ---

3,2.2 DI-MISC-80073 Armoc Material Test Reports Format

(copies of data item descriptions related to this specification, and

identified in section 6 will be approved and listed as such in DOD 501O.12L,Vol. 11, AMSDL. Copies of data item descriptions required by the contractorsin connection with specific acquisition functions should be obtained from theStandardization Documents OrdeK Desk, Sldg. 4D, 700 Robbins Avenue,Philadelphia, PA 19111-5094

6.3 Thickness. The symbol ‘T” is used throughout this specification to

indicate the nominal thickness of the plate under consideration.

I

6,4 Definitions.

6.4.1 Contractor. The contractor is the company which has a directcontract from the Government to furnish an end item - usually a vehicle. Alsoknows as the prime contractor.

6.4.2 Contracting officer. The term “contracting officer” means theperson executing a contract on bebalf of the Government and any other officeror civilian employee who is properly designated contracting officer; and theterm includes, except ae otherwise provided, the authorized representative ofa contracting officer acting within the limits of his authority.

6.4.3 Homogeneous rolled armor. Homogeneous rolled a~m?r is armor having

uniform composition and heat treatment throughout.

6.4.4 Manufacturer. The manufacturer is defined as the company producingthe steel alloy plate.

6.4.5 Procuring activity. The term ‘procuring activity” iS that aCtiVitYof the Government which actually initiates the request for procurement and

maintains tbe records of the procurement.

6.4.6 Slivere. An imperfection coneiating of a very thin elongated Pieceof metal attached by only one end to the parent metal into whose surface it

has been worked.

6.4.7 ~. A surface imperfection with the appearance Of a seam,.caused

by hot metal, fins or sharp corners being folded Over and thus being fOrged Orrnlled into the surface but without being welded.

6.4.8 _. Numerous very fine cracks at tbe aurfac~ Of a metal Part.Checks may appear during processing or during service and are most often

associated with thermal cycling or thermal treatment. Also called check

markg, checking, heat check8.

20

I MIL-A-12560H(MR)

6.4.9 g. An unwelded fold, or lap that appears as a.crack, usuallY

resulting from a discontinuity on a metal surface.I

~6.4.10 Blisters. A raised area, often dome shaped, resulting from

delamination under pressure of expanding gas trapped in a metal in a near

sub-surface zone. Very small blisters may.be called pinhead blishers OKpepper blisters.

~

6.4.11resembling

=. Any crooked surface imperfection in a metal plate,a Snake,

Cold shuts. Freezing of tbe top surface of an ingot before mold6.4.12is full.

6.4,13 Burning. Permanently damaged metal due to overheating enough tocause incipient melting or intergranular oxidations. Note: This condition is

usually obscured by normal cleaning methods and would require deep pickling

and/or metallography to note tbe continuous oxidation (chicken wire effect) ofthe enlarged grain boundaries.

6.4.14 Lamination. A type of discontinuity with separation or weaknessgenerally aligned parallel to direction of the worked surface of the Metal and

way be tbe result .ofpipe, blisters, seams, inclusions, Or ae9re9ati0njelongated and made directional by working.

6.4.15 ~. A cavity or depressed area on tbe surface of “a plate.

6.4.16 Linear indication. For nondestructive eXaIhinakiOn purposes, alinear indication is evidence of a discontinuity that requires interpretationto determine its significance.

6.5 Changes in composition. Changes in composition shall not necessarily

be cause for retesting but shrill be subject to review by the procuringactivity to determine whether additional ‘first article testing is required.

6.6 Chemical Analysis. Suggested ASTM instrumental Methods that can beused are chemical analysis E415, E282, E484 and E322. ASTM A751 should beconsulted for a complete list of methods.

6.7 MIL-STD-367 . Format I of MIL-STD-367 replaces POKm MIL12560 and TACForm 3983,

6.8 Potential suppliers. Potential suppliers who have not previously

supplied armor plate to ‘MIL-A-12560 and wish to have their’material

ballistically tested, may do so at their own expense. It is recommended thatinquiries for such testing be directed to Commander, US Army CSTA, AT2Ti:STECS-LI-A,. Aberdeen Proving Ground, MD 21005-5059.

6.9 New contracts sponsored by government agencies. At tbe time that a

new contract is initiated for the production. of combat vehicles, thecontractor’s supplier is to ‘estimate the number, size and delivery schedule ofthe ballistic test plates which are to be submitted for first article or

acceptance testing. A lead time of 60 days after tbe contract has been signed

is to be allowed prior to shipment of the first ballistic test plate(s) to AFG

21

MIL-A-12560H(MR)

to insure that all administrative functions for the establishment of a new

TECOM pto]eCk have been completed in preparation for the teat, The

contracting government a9ency is to initiate the new project through a letterto Commander, US Army TECOM, ATTN: AMSTE-TA-0, APG, MD 21005-5055 requesting

a cost estimate for the ballistic testing of the applicable number of sizes ofplates. In the case of increases in scope of existing projects, similar

correspondence is needed.

6.10 Metric units. When metric dimensions are required, units for inch,

foot, foot-pounds and feet Psr second may be converted to the metricequivalent by multiplying them hy the following conversion factors:

To go from TO getEnglish Multiplv by Metric S1 unitinch 0.0254foot

metre (m)0.3048 metre (m)

foot-lb 1.3558 joule (J)

feet/see 0.3048 metre per second (m/s)

NOTE: COnVer SiOn faCtOKS Can be associated with ASTM E380 entitled ‘MetricPractice Guide. m

6.11 Special first article ballistic test. Special first article

ballistic tests are required when tbe manufacturer changes either the meltingprocedure or heat treatment or the declared chemistry of tbe armor.

6.12 Fabrication. The armor plate covered by this specification iseubject to fabrication involving cutting, drilling, forming and welding. Itis intended that selection and control of chemical composition, cleanliness,and plate processing will be ouch that the armor will be suitable forfabrication under procedures and controls such as specified fn MIL-STD-1941,Metal–Arc Welding of Homogeneous ArIiIOr.

6.13 Production plates. Material made to this specification has a

tendency to develop stress cracks if not tempered as Boon as possible after

austenizing treatment. TO avoid this situation all plates should be left inthe hot-rolled or tempered condition while waiting for the ballistic testresults.

6.14 Subject term (key word) Iistinq

AKMOK plate 0.30 caliber AP, M2 projectile

Steel 20 mm AP-T, M602 projectile

Homogeneous 5 mm AP, M70 projectile

Ballistia limit 90 mm AP, M318 projectile0.50 caliber API M2 projectile 90 mm AP, M82 projectile

6.15 Changes from previous issue. Marginal notations are not used in this

revision to identify changes with respect to the previous issue due to theextensiveness of the changes.

.,,,2.2

Custodian:Army - NR

Review activi ties:

Army - AR, Al’,AV,DLA - 1S

MIL-A-12560H(MR)

TE

I(WP# ID-0186A/DISK-0207A. FOR MTL USE ONLY)

Preparing activity:Army - MR

Project 9515-A057

23

MIL-A-12560H(MR)

APPENDIX

BALLISTIC TESTING OF AiMOR, STEEL PLATE, WROUGHT, HOMOGENEOUS

10. SCOPE

10.1 This appendix covers the requirements for ballistic testing ofwrought homogeneous steel armor plate.

20. DEFINITIONS

20.1 Fair impact.

20.1.1 Caliber .30 AP through 20 mm tests. A fair impact 16 an impactresulting from tbe striking of the test plate by a projectile in normal flight

(KKOeXCeSSiVe YaWin9 or tumbling) and separated from another impact or theedge of the plate, hole, crack or spalled area by an undisturbed area of at

least two test projectile diameters.

20 ,1.2 57mm AP and larger calibers. A fair impact is an impact resulting

from the striking of the test plate by a projectile in normal flight (no

yawing or tumbling) and separated frDm anothez impact or from the edge ofplate, hole, crack or spalled area by at least one test projectile diameter ofundisturbed area.

20.2 witness plate. A witness plate is nDrmally a 0.014 inch thick sheetof 5052 aluminum alloy (or a 0.020 inch thick sheet of 2024-T3 aluminum alloyplaced 6 inches (~ 1/2 inch) behind and parallel to tbe test plates or otherballistic sample,

20,3 Complete penetration, protection, CP (P).

20.3.1 For caliber .30AP M2 through 20mm API-T M602. A protection

complete penetration occurs when the projectile oc one or more fragments of a

projectile or plate pass beyond the back of the test plate and perforates thewitness plate.

20.3.2 For Projectiles larger than 20mm. A protection complete

penetration occurs when one ‘ormore fragments of a projectile or plate has

been ejected from the rear of the plate as determined by visual inspection.

20.4 Partial penetration, protection, PP (P). ‘A partial penetration is

any impact that is not a complete penetration.

20.5 ~. The difference in velocity between the high partialpenetration velocity and the low complete penetration velocity used incomputing the ballistic limit where the high partial penetration velocity is

lower than the low complete penetration velocity.

~MIL-A-12560H(MR)

APPENDIX

20.6 Protection ballistic limit, BL(P).

20.6.1 Caliber .30 AP, M2 caliber .50 AP M2, 20NN API-T M602 penetration=. The BL(P) shall consist of an equal number of fair impact complete and

partial penetration velocities attained by the up-and-down firin9 method. All

EL(P) ‘s shall be computed using the highest partial penetration velocities andthe lowest complete penetration velocities. Firing shall continue untileither a 4 round BL(P) having a maximum velocity spread of 60 fps or a 6 round

BL(P) having a maximum .velocity spread of 90 fps has’been attained, whichevercomes first in the normal .vequence of firing. If both occur simultaneously,

the 6 round BL(P) will be reported. f.

20.6 .1.1 In the event that the zone of mixed results (difference betweenthe high partial penetration velocity and the low complete penetration

velocity, the PP(P) velocity being bigber. than the low CP(P ) VelOCitY) exceeds

~90 fps, the firing data will be compared. with the specification minimumballistic requirements. If the lowest complete penetration VelOCitY iS eqUalto or above the minimum specified ballistic limit velocity for the plate

thickness, the ballistic limit will be computed on the basis of 4 or 6 roundsusing the smallest possible velocity spread. If the lowest. complete

penetration velocity is below tbe m“inimum allowable ballistic limit velocitythen testing will continue until a ten round ballistic limit has been attainedusing the smallest possible velocity spread.

20.6.2 57mm AP, M70 and larger caliber projectiles. For the purpose ofthis specification, the protection ballistic limit is the average of four fair

protection criteria impact velocities comprising tbe first two lowestvelocities in the firing order resulting in complete penetrations and thefirst two highest velocities in the firing order resulting in partial

penetrations which meet the condition that the velocitY spread fOr the 4rounds shall not exceed 100 fps.

20.6.3 Reduction of large velocity gap in borderline cases. If theballistic limit which has been determined is within ~ 10 fps from the minimumallowable ballistic .limit and a gap exists which is greater that 25 fps, thenanother round, or rounds, will be fired to reduce the gap to 25 fps or less.The ballistic limit will then be recomputed using the criteria of paragraphs20,6.1 or 20.6.2 as applicable. The recomputed BL(P) will be reparted as ‘tie

BL(P) of tbe plate (in borderline cases a reduction of the gap between thehigh partial penetration velocity and the low complete velocity should resultin a better evaluation of the BL(P) .

30. REQUIREMENTS

30,1 Resistance to peiletration. The minimum acceptable ballistic Iimits

shall be in accordance with the values shown in tables X through SVII.

30,1.1 For class 3 armor plate, upper ballistic limit (maximum) values

shall be as specified in the applicable footnotes

-25

of tables X through XVII.

MIL-A-12560H(MR)

. .

APPENDIX

30.2 Back spallinq,

30,2.1 Plates 1/2 to 11/16 inch in thickness. Plates of these orderedthickness shall bs .vubjectsd to a backspall test consisting of firing two

rounds of 20 mm AP M95 ammunition at a 0° obliquity at the test 91ete. The

striking velocity shall be in the velocity range of 2500-2550 fps. The

maximum allowable backspall dimension shall be 1 5/8 inches.

30.2.2 Plates 3/4 inch and greater in thicknsss. Spalling shall notexceed 2.0 tsst projectile diameters after proof firing at normal obliquityaccordance with the appropriate table of the Appendix, and shall not exceed

2.5 test projectile diameters in the case of oblique psnstration tests.

30.3 Crackinq.

30,S.I 00 ~b~iquity attack. Immediately after ballistic testin91

plates subje=ted to 0° obliquity attack shall not develop any crack which,

when measured from the center of impact, extends outside a circle having aradius equivalent to twice the test projectile diameter.

30.3.2 Oblique attack. Immediately after ballistic testing, platessubject to oblique attack shall not develop any crack which, when meaeured

in

from the center’of impact, extends outside a circle having a radius equivalentto three test projsctile diameters.

30.4 Rejection. Failure to meet any of the ahove requirements shall becauee fOK plate rejection.

40. TESTS

40,1 Ballistic teStB. v50 ballistic tests shall be peffOrm@d inaccordance with USATECOM TOP 2-2-710, Ballistic Tests of Armor Materials to

determine compliance with the requirements of tables X through XVII.

40.1.1 Plate thickness as measured by the ballistic test agency shall be

used to detecmine the required ballistic limit for the plate. The required

ballistic limit will be determined by interpolation of the tabled”’in theAppendiX, if necessary.

40,1.2 Lift hole requirement for test plates.

40,1.2.1 Ballistic acceptance testing plates.

a. Ballistic acceptance test plates far either class 1 or armo~ which areless than 2.751 inches ordered thickness are to be supPlied without a liftinghole.

b. Ballistic acceptance test Plates for either Class 1 or 3 armor whichare 2.7.5.1 inches through 6.25 inches thick shall be provided with 3-inchdiameter lifting holes, one in each of two adjacent sides an showh in figure 1.

26

II MIL-A-12560H(MR)

~

APPENDIX

40.1.3 Rejection and retest of ballistic plates.

‘40.1.3.1 First article tests (rejection). Unless noted otherwise in the

contract or order, failure of any one or more of the three first article”.test ..?<plates to meet the minimum’ ballistic requirements as specified “in the APPendixto this specification indicates failure of the product and process.

40.1.3.2 First artiCle (Ket&tS). Resubmission of ballistic retest plates

shall not be made until the manufacturer has made the necessary corrections inthe processing of the material to the satisfaction of the procuring activity.Three retest plates must “be submitted for first article testing and all three

I must pass.

40.1.3.3 Acceptance tests (rejection) . Unless otherwise noted in the

contract OK order, failure of a test plate tO.meet the ballistic requirement

indicates failure of the lot, however, the final decision will depend on theoutcome of retests,. if submitted.

40.1,3.4 Acceptance tests (retests). If a test plate representing a lotfails to meet the ballistic requirement, the manufacturer has the following

options: Immediately upon notification of the failure, he may:

(1) At his Own expense submit two additional test plates from the samelot for ballistic retest, or

(2 ) He may first re-beat treat (quenching. and tempering] the lot andthen submit a test plate from the re-treated lot, or

(3) He may scrap the lot and submit a plate representing a new lot foracceptance.

If he chooses any one of these options and the ballistic. retest plate (orplates) meet the requirements then the lot represented is acceptable. If he

, chooses option (1) and one or both of tbe retest plates fail, the manufacturermay ce-heattreat the lot and submit a test plate from tbe retreated lot. If

this plate fails tbe lot is rejected. If he chooses option (3) and the testplate fails, he may again resort to any one of the ‘three options.

40.1,4 Disposition of ballistic test plateS.

40.1.4.1 First article test plates. upon request of the applicant within

15 days after ballistic testing, first’ article plates will be returned “as isnto the applicant, at bis expense, unless the plates were destroyed in testing.

40,1.4,2 Acceptance test plates. Acceptance test plates that comply withthe requirements of this specification are considered as part of the lot ofsteel they represent and ownership of them passes to tbe Government with tbe

acceptance of that lot. Acceptance test plates that fail to comply with the

requirements of this specification are considered as part of the lot theyrepresent and remain tbe property of the producer just as the rejectable lotdoes. The failed plates will be returned, upon request, as in 40.1.4.1.

27

NIL-A-12560 H(MR)

APPENDIX

TABLE X. Minimum required ballistic limits (protection criteria)

firing obliquity: OO; projectile: Caliber .30AP, M2.

Thickness, Required Thickness, Required Thickness, Requiredinchss BL(P), fPS inches BL(P), fDS inches BL(P), fps

0,230.235

.240

.245*.250

.255

.260,265

,270.275.280

.285,290.295

.300

.305

.310

.315

.320

.325

.330

.335

.340,345

15091532

155415751596

161816381659

167916991719

173917581778

1797181518341853187118891907

192519421960

0.355.360

.365

.370

.375

.380

.385

.390

.395,400.405

.410

.415

.420

.425

.430

.435

.440

.445

.450

.455

,460.465.470

19942011

202820452062

2u7820952111

21272143215921752191

2206

2222223722522267228222972312

23272342

2356

0.480.485

.490

.495

.500

.505

.510

.515

.520

.525

.530

.535

.540

.545

.550

.555

.56o**,565

,570.575.580

.585

.590

.595

23852400

241424282442

245624702484

249825122525

253925S22566

2579259326062619263226452658

267126842697

,330 1977 .475 2371 .600 2710*Specification requirements begin for this ordered tbicknese.

NOTE 1:

NOTE 2:

**specification requirements end for this ordered thickness.

Tabulated values on either side of the specification requirements

are for interpolation of BL(P) requirements on undersize or over-size plates.

For Class 3 armor the upper ballistic limit (maximum) shall not begreater than 141 fps above tbe required lower ballistic limit(minimum).

28

MIL-A-12560 H(MR]

APPENDIX

TABLE XI. Minimum required ballistic limits (protection criteria)firing obliquity: OO; projectile: Caliber ..50 AP, M2.

Thickness, Required Thickness, Required Thickness, Required

inches EL(P), fps inches “BL(P), fps inches t3L(P), fps

0.550 1901 9.765 2305 0.985 2658

.555

.560

.565*.566.570

.575

.580

.585

.590

.595,600

.605

.610.,615

.620

.625

.630

.635

.640

.645

.650

.655

.660

.665

.670

.675

.680

.685

.690

.695

.700

.705

..710.715.720

.725

.730

.735

.740

.745

.750

19111922

193219341942

195219621972198219922002

201220222031

204120512060207020792089209821082117212621362145

215421632173

218221912200220922182227223522442253226222712279

.770

.775

.78IJ

.785

.790

.795

.800

.805

.810

.815

.820

.825

.830

.B35

.840

.845

.850

.855

.860

.865

.870

.875

.880

.885

.890

.895

..900.905.910

.915

.92o

.925

.930

.935

.940

.945

.950

.955

.96o

.965

.970

.975.

23142322

233123392348

235623652373

23822390

2398

240624152423

243124392447245524642472248024882496250425112519

252725352543

.255125592566

257425822590

2597

26052612

262026282635

2643

0.9900.9951.0001.0051.010

1.0151.0201.0251.0301.035

1.040

1.0451.0501.055

1.o6o1.0651.0701.0751.0801.0851.0901.0951.1001.1051.1101.1151.120

**1.1251.130

.1,1351.140’1.145

1.1501.1551.1601.165

1.1701.i75

1.1801.1851.190

.755 2288 1.195

.760 2297 .980 2650 1.200*Specification requirements begin for this ordered thickness.

26b52673268026882695

2702271027172724

2732

2739

274627542761

276827752782279027972804281128182825283228392846

2B5328602867

2874288128882895290229092915

29222929

293629432949

29562963

**s~ecification requirements en: for this ordered thickness.

NOTE 1: Tabulated values on either side of the specification requirements arefor interpolation of BL(P) requirements on undersize or oversize plates

NOTE 2: For Class 3 armor tbe upper ballistic limit (maximum) shall not beVgreaterthan 146 fps above the required lower ballistic limit (minimum).

7Q

TABLE XII ,

MIL-A-12560H(MR)

APPENDIX

Minimum required V50 ballistic limits (protectioncriteria) firing obliquity 0°, projectile caliber20mm AP-T, M602.

ThicknesB Required Thickness Required Thickness Required

Inches BL(P) ,FPS Inches BL(P), FPS Inches BL(P),FPS

1.100 1933 1.370 2234 1.650 25051.110 1945 1.380 2244 1.660 25141.120 1957 1.390 2254 1.670 2524*1.126 1964 1.400 2265 1.680 25331.130 1969 1.410 2275 1.690 25421.140 1981 1.420 2285 1.700 25511.150

1.1601.1701.1801.1901,2001.210

1.22(I1.2301.2401.250

1.2601.2701.2801,2901.300

1.3101.320,1.330

1.3401.3501.360

19932004201620272039

20502061

2073208420952106

21172128213921492160217121812192

220322132223

1.4301,4401.4501.4601.4701,4801.490

1.5001.5101.5201.530

1.5401.5501.5601.5701.5801.5901.6001.610

1.6201.6301.640

2295230523152325

233523442354

2364237423832393

24032412242224312440245024592468

247824872496

1.7101.7201.7301.740

1.7501.7601.770

1.7801.7901.8001.810

1.8201.8301.8401.8501.860

1.8701.8801.890

1.9001.9101.920

2560256825862595260426132613

2621263026392647

26562664267326812690

269827072715

272327322740

30

MIL-A-12560H(MR)

APPENDIX

TABLE XII , Minimum required V50 ballistic limits (protection

criteria) firing obliquity 00, projectile calibei20mm AP-T, M602. (Continued)

Thickness Required Thickness Required Thickness

Inches

RequiredBL(P), FPS Inches BL(P), FPS Inches BL(P), FpS

1.930 .2748 2.250 3000

I1.940 2757. 2.260 3008

1.950 2765 2.270 3015I 1.960 2773 2.280 3023

1.970 27S1 2.290 3030. . . .1.9801.9902.0002.010

2,020

2.0302,0402,050

2.0602.0702.0802.090

2.1002.110

2.1202.1302.1402.1502.1602.170

2.1802.1902.200

2.2102.2202.230

2.240

27S927982S062S14

2822

2S3038383S46

285428622870

287728852S93290129092916292429322940

294729552963

29702978.29S5

2993

2.3002.3102.3202.330

2.340

2,3502.3602.37o

2.3802.3902.4002.4102.4202.4302.44o2.4502.46o2.4702.4802.49o

2.500‘2.51O2.5202.5302.5402.550

2.S60

3038304530523060

3067

307530823089

309631043111.3118

31253132

3140314731543161316S3175

318231893196

320332103217

3224

2.570

2.580.2.5902.6002.6102.6202.6302.640

2.650

2.660

2.6702.6802.690

2.7002.7102,7202.7302.740

** 2.7502.7602.7702.7802.790.2.8002.810

.32313238324532523259326532723279

3286

3293

3299.33063313

3320

3326333.3.3340

33463353336033663373

338033863393

* Specification requirements begin for this ordered thickness.**specification requirements end for this ordered thickness.

NOTE : Tabulated values on either side of the specification requirements arefor interpolation of,BL(P) requirements on undersize or oversize plates.

31

MIL-A-12560H(MR)

APPENDIx

TABLE XIIA. Upper ballistic limits for class 3 armor firing

obliquity O degrees, projectile 20 mu AP-T, M602.

!rhiokness Required Thickness Required Thickness RequiredInches BL(P), FPS Inches BL(P),FPS Inches BL(P),FPS

1.1001.110

1.120*1,126

1.1301.140

1.1501.160

1.1701.1801.1901.200

1.2101.220

1.2301.240

1.2501.2601.2701.280.

1.2901.3001.3101.320

1.3301.340

1.3501.3601.3701.3801.3901.400

; 1,4101.420

1.4301.440

2.4502.460

2.4702.480

2042

2055206S207620812094

21062119

213121442156216921812193

220522172229224122532265227722892300231223232335

23462358236923S0239224032414242524362447245S246924802491

1.4901.500

1.5101.5201.5301.5401.5501.560

1,5701.5801,5901.600

1.6101.6201.6301.6401.6501.6601.6701.6801,6901.7001.7101.7201.7301.740

1.7501.7601.7701.7801.7901.s001.8101.8201.8301.s401.s501.8601.8701.880

2501

2512252325342544255525652576

25S6259726072617262826382648265S2668

2678268926992709271927282738274S275S

2768277s27S7

27972807281628262836284528552S64287428832892

1.s90

1.900

1.9101.9201.9301.940‘1.9501.960

1.970

1.9801.9902.0002,0102.020

2.0302.0402.0502.0602.0702.0802.0902.1002.1102.1202,1302.140

2.1502.1602.170

2,1802.1902.2002.2102.2202.2302.2402.2502.2602.2702.2B0

2902

2911

292129302939

2948295829672976

29852994300330123021303030393U48

3057306630753084309331023H031193128

313731453154

31633171318031883197320632143223

32313240

3248

32

I MIL-A-12560H(MR)

APPENDIx

~TABLE XIIA. ‘~er ballistic limits for class 3 armor firing obliquity

O degrees, projectile 20 mm AP-T, M602. (Continued)

Thickness Required Thickness Required Thickness Required

~

Inches BL(P), FPS Inches BL(P),FPS Inches .BL(P),FPS

2,290 3257 2.470 3405 2.650 3548

2.300 3265 2.480 3413 2.660 3556

I

2,310 3273 2.490 3421 2.670 35632.320 3282 2.500 3429 2.680 35712.330 3290 2.510. 343-1 2.690 3579

2.340 3298 2.520 3445 2.700’ 35862.350 3307 2.530 3453 2.710. 3594

~

2,360 3315 2.540 3461 2.720 36022.370 3323 2.550 3469 2.730 3610

2,380 3331 ‘2.560 3477 2.740 3617

2.390 3340 2.570 3485 ** 2.750 36252.400 3348 2.580 3493 2.760 36322.410 3356 2.590 3501 2.770 36402,420 “3364 2.600 3509 2.780 36482.43(I 3372 2.610 3516. ‘2.790’ 36552.440 3381 2.620 3524 2.800 36632.450 3389 2.630 3532 2.810 36702.460 3397 2.640 3540.

* Specification requirements begin for ‘this ordered thickness.** specification requirements end for this ordered thickness.

33

MIL-A-12560H(MR)

APPENDIX

TABLE xII1. Minimum re~red V50 ballistic limits (P ),rotection criteria

firing obliquity 450, projectile caliber 90 mm APC, M82.

Thickness, Required Thickness, Required Thickness, Required(inch) BL(P), fPS (Inch) EL(P), fps (inch) BL(P) , fPs

2,7002.710

2.7202.7302.7402,750

*2.7512.760

2.7702.7802.7902.8002.8102..820

2,8302.840

2.8502.860

2.8702.8802.8902.9oO2.9102.9202.9302.940

2.9502.960

2.970

20952101

210721132119212521262131

2137

21432149

215521612167

217321792185219021962202220822142220222522312237

22432248

2254

2,9802,990

3.0003.010

3.0203.0303.0403,050

3.060

3.0703.0803.0903.1003.110

3.1203.130

3.1403.1503,1603.1703.1803,1903.200

3.2103.2203.230

3,2403.2503.260

22602265

22712277,2282228822942299

2305

23102316232223272333

23382344.234923552360

2366237123762382

238723932398240424092414

3.2703.280

3,2903.3003.310

3.3203.3303.340

3.3503.3603.3703.3803.3903.400

3.4103.4203.4303.4403.4503.4603.470

3.48o3.490

**3.5003.5103.5203.5303.5403.5503.560

24202425

243024362441

24462451

2457

2462

246724722478248324882493249824o4250925142519252425292534

254025452550255525602565

257o

* Specification requirements begin at 2.751 inch ordered thickness.** specification requirements e“d at 3.500 inch ordered thickness.

NOTE : For class 3 armor the upper ballistic limit (maximum) shall not begreater than 293 fps ahove the required lower ballistic limit

(minimum).

34

,.

MIL-A-12560H(MR)

APPENDIX

TABLE XIV. Minimum required V50 ballistic limits (protection criteria) ;

firing obliquity: 3130:projectile: 90mm APC, M82.

Thickness, Required Thickness; Required Thickness,inches.

RequiredBL(P) , fPs inches BL(P), fps inches BL(P), fps

3.4253.430

3.4353.4403,4453$4503.4553.460

“3.4653.470

3.4753.4803.4853.4903.4953.500

* 3.5013,505

3.5103.515

3.5203.5253.5303.5353.5403.545

3.5503.5553.5603.5653.5703.575

3.580‘.3.585

3.5903.5953.6003.605

3.6103.615

19241926

192919311933

193519371939194219441946194819501952195419571957195919611963196519671969197119741976

197819B01982198419861988

199019931995199719992001

20032005

3.62o3.625

3.63o3.6353.640

3.6453.6503.6553.6603.665

3.67o3.6753.6803.6853.6903.6953.7003.7053.7103.7153.72o3.7253.7303.7353.7403.745

3.7503.7553.7603.7653.7703.775

3.7B0.3.785

3.7903.7953.8003.805

3.8103.815

35

20072009

201120132015

201820202022202420262028203020322034203620382040204220442046

2048205120532055

20572069

2061206320652067 ,20692071

20732075.207.72079208120B3

20852087

3.8203.825

3.83o3.8353.840,3.8453.B503.8553.8603.8653.8703.8753.8803.8853.89o3.8953.9003.905

3.9103.915

3.9203.9253.9303,9353.9403.945

3.9503.955’3.9603.’9653.9703.975

3.98o3.9853.9903.9.95

** 3.9994.000

4.0054.010

20892091

20932095209720992101210321052107

21092111211321152117211921212123

21252127

2129213121332135

21372139

214121432144214621482150

215221542156215821602160

2162

2164

APPENDIX

TABLE XIV . Minimum required V50 ballistic limits (protection criteria) tfiring obliquity: 30°; projective: 90mm APC, M82. (Continued)

Thickness, Required Thickness, Required Thickness, Requiredinches BL(P), fps inches BL(P), fps inches BL(P), fps

4.015 2166 4.035 2174’ 4.055 21814.020 2168 4,040 2176 4,060 2183

4,025 2170 4.045 2178 4.065 21854.030 2172 4.050 2179 4.070 2187

* specification requirements begin for this ordered thickness.** specification requirements end for this ordered thickness,

I NOTE 1:

NoTE 2:

Tabulated values on either side of the Specification CeqU1rementS are.for interpolation of EL(P) requirements for undersize or oversizeplates.

For Class 3 armor tbe upper ballistic limit (5% rejection) shall not

be greater than.192 fps above the required lower ballistic limit.

36

MIL-A-12560H(MR)

APPENDIX

TABLE XV. Minimum required V50 ballistic limits (protection criteria) :firing obliquitv: O ; projectile: 90mm Ap, M318, Al.

Thickness, Required Thickness, Required Thickness, Required

inches BL(P), fPS inches EL(P), fPS inches BL[P), fps

3.9403.950

3.9603.9703.980

3.990* 4.000

4.010

4.0204.0304.040

4.0504.0604.070

4.0804.0904.1004.1104.1204.1304.140

4.1504.160

4.1704.1804.190

4.2004.2104.2204.2304.2404.250

4.2604.2704.280

4.2904.3004.310

4.3204.330

1583 4.340

1586 4.350

1590 4.3601594 4.3701597 4.380

1601 4.3901605 4.400

1608 4.410

1612 4.4201616 4.4301619 4.440

1623 4.450

1627 4.4601630 4.470

1634 4.4801637 4.4901641 4.5001644 4.5101648 4.5201652 4.5301655 4.540

1659 4.5501662 4.560

1666 4.570.1669 4.5801673 4.590

1676 4.6001680 4.6101683 4.620

1687 4.6301690 4.6401694 4.650

1697 4.6601701 4,6701704 4.680

1708 4.6901711 4.7001714 4.710

1718 4.7201721 4.730

,,.31

17251728

173117351738

174217451748

175217551758

1762176517681772177517781782178817921795

17981783180118051808

181118151818

182118241827

183118341837

i84018441847

18501853

4..7404.750

4.7604.7704.780

4.7904.8LI04.810

4.8204.83o4.840

4.85o4.860‘4.8704.8804.8904.9004.9104.9204.9304.940

4.9504.9604.9704.9804.990

5.0005.0105.0205.0305.0405.050

5.0605.0705.080

5.0905.1105.110

5.1205.130

18561860

18631866

1869

187218751878

188218851888189118941897190019031907191019131916191919221925192819311934

193719401943194619501953

195619591962

196519681971

19741977

MIL-A-12560LI(MR)

APPENDIX

TABLE XV, Minimum required V50 ballistic limits (protection criteria) Jfiring obliquity: O ; projectile: ,Omm AP, M318, Al. (Cont!d)

Thickness, Required Thickness, Required Thicknes8, Requiredinches BL(P) , fps inches BL(P), fps inches i3L(P), fps.

5.14D 19805.150 19835.160 19865,170 19895.180 19925.190 19955,2oo 19985,210 20015.220 20035.230 20065.240 20095.250 20125.260 2015

5,270 20185.280 20215.290 20245,300 20275.310 20305,32o 20335.330 20365.340 20395.350 20425.360 20455.370 20475.380 20505.390 20535.400 20565.410 20595.42o 2062

.5.430 20655,440 20685.450 20705.460 20735.470 20765,48o 2079

5.490 20825.500 20855,510 20885.520 2090

5.5305.5405,5505.5605.570

5.5805.5905.6005.6105.6205.6305.6405.650

5.660

5.6705.6805.6905.7005.7105.7205.7305.7405.750

5.7605.7705.780

5.7905.8005.810

5.8205,8305.8405.8505,8605.870

5,8805.8905.900

5.910

20932096

209921022105

210721102113211621192121212421272130

213321352138214121442147214921522155

215821602163

216621692171217421772180

218221852188

219021932196

2199

5.9205.930

5.9405.9505.960

5.9705.9805.990

6.0006.0106.0206.0306.o4O

6.050

6.0606.0706.0806.0906.1006.1106.120

6.1306.140

6.1506.1606.170

6.1806,1906.200

6.2106.2206.2306.240

** 6.2506.260

6.2706.2006.290

6.300

22012204220722092212

221522172220

222322262228223122342236

22392242224422472249225222552257226o

226322652268

227222732276

22782281228422862.2892291

229422972299

2302

* Specification requirements begin for this ordered thickness.** specification requirements end for this ordered thickness.

NOTE .1: Tabulated values .on either side of the specification requirements are

for interpolation of BL(P) requirements on undersize or oversize

plates.NoTE 2: For ClaSs 3 armor the upper ballistic limit [5% rejection) shall nOt

be greater than 202 fps above the required lower limit (minimum).

38

MIL-A-12560H(MR)

+P-+4a~ .L,

JJ . .FIGURE 1. Lifting holes for ballistic acceptance test

plates 2.751 through 6.25 inches thick.

39