archer airguns xmv tune kit for ruger

Archer Airguns XMV Tune Kits for Ruger Air Hawk and Blackhawk Air Rifles

Also fits the Ruger Air Hawk Elite, Ruger Air Hawk Magnum, RWS Diana 34, Xisico XS25 series and XS28M Air Rifles.

Note that, throughout, all thickness and depth measurements are given in thousandths of an inch “thous”.

XMV Tune Kit parts fit both .177 and .22 caliber air rifles.

Diagrams are not drawn to scale.

Ruger and Blackhawk are registered trade marks of Sturm Ruger Inc, used by Umarex USA Inc.

Contents:

1. Ruger Air Hawk .177 Caliber Test Target! ! ! Page 2

2. Overview! ! ! ! ! ! ! ! Page 3

3. Precision Components! ! ! ! ! ! Page 4

4. Theory of Operation! ! ! ! ! ! Page 4

5. Donʼt Shim Too Much!! ! ! ! ! ! Page 7

6. Will the XMV Tune Kits Improve My Air Rifle?! ! Page 8

7. Installation Steps!! ! ! ! ! ! 1

8. Test Results for .22 Caliber Xisico XS25 Air Rifles! ! Page 13

Archer Airguns XMV Tune Kits for Ruger Air Hawk and BlackHawk Air Rifles! Page 1____________________________________________________________________________________

____________________________________________________________________________________ Copyright Stephen Archer, Archer Airguns Inc.! June 2012

1. Hereʼs What a Ruger Air Hawk Can Do!

Using the Archer Airguns XMV Tune and Pellet Kit, this Air Hawk shoots at over 1150fps, producing 16.7 ft/lbs of muzzle energy with excellent accuracy and consistency. Yet this gun started out at just 806fps when new!

Archer Airguns XMV Tune Kits for Ruger Air Hawk and BlackHawk Air Rifles! ____________________________________________________________________________________


2. Overview:

Archer Airguns XMV Tune Kits give the precision parts and expert information you need to custom tune your gun - gaining significant fps - within minutes and without the need for a chronograph. They enable you to gain the maximum performance from your Ruger Air Hawk or Blackhawk air rifle at low cost while being simple to do. Very importantly, no irreversible changes or modifications are required to your airgun. And you can have fun doing it!

The Archer Airguns XMV Tune Kit for Ruger Air Hawk and Blackhawk Air Rifles provides a significant increase in muzzle velocity of 80fps - or even more - compared to an average “out of the box” gun in .177 caliber, an increase of over 20% in muzzle energy using the same pellets. It does this with no requirement for permanent modifications to the air rifle or the need for specialist tools. The contents include:! 3 precision machined steel shims! 3 high-quality, high durometer breech seals (2 are spares)! Comprehensive illustrated instructions

The Archer Airguns XMV Tune and Pellet Kit for Ruger Air Hawk and Blackhawk Air Rifles provides a huge increase in muzzle velocity of 350fps - or even more - an increase of around 30% in muzzle energy compared to shooting average lead pellets. It also does this with no requirement for permanent modifications to the air rifle or the need for specialist tools. The contents include:! 3 precision machined steel shims! 3 high-quality, high durometer breech seals (2 are spares)! Comprehensive illustrated instructions! German-manufactured precision Stoeger X-Speed lead free pellets

The XMV Tune Kit has been developed by an exhaustive analysis of the barrel/breech seal/compression tube interface of these air rifles; a major cause of muzzle velocity loss in standard factory guns. The XMV Tune and Pellet Kit enhances that analysis by selecting high quality pellets for optimum performance in these air rifles.

The following table illustrates the improvements achieved using these XMV Tune Kits kits with the same Ruger Air Hawk air rifle:



Ruger Air Hawk Condition (gun was fired sufficiently to eliminate dieseling before testing started)

Tested Pellets

Seal Projection

(thou)

Muzzle Velocity

(fps)

Muzzle Velocity Increase

Over Factory

Condition

Muzzle Energy (ft/lbs)

Muzzle Energy

Increase Over

Factory Condition

“Out of the box” from factory Stoeger X-Field 8.56

Grain

-8 806 N/a 12.4 N/a

Factory breech seal with optimum shim thickness

Stoeger X-Field 8.56

Grain

12 849 43 13.7 11%

Replacement breech seal with optimum shim thickness (Archer Airguns XMV Tune Kit)

Stoeger X-Field 8.56

Grain

14 886 80 15.0 21%

Replacement breech seal with optimum shim thickness and lighter pellets (Archer Airguns XMV Tune and Pellet Kit)

Stoeger X-Speed

5.66 Grain

14 1153 347 15.9 28%

3. Precision Components

Archer Airguns XMV Tune Kits look simple, but they comprise high precision components that ensure you achieve the benefits you want in your Ruger Air Hawk or Blackhawk air rifle.

The steel shims are precision machined to tolerances of half a thousandth of an inch thickness.

The breech seals have a higher durometer rating than the factory seals. They also have a slightly greater thickness. This provides improved air tightness - eliminating lost air that reduces muzzle velocity. These breech seals are also 300% more consistent in thickness than the factory part. This is a very important benefit!

Both shims and breech seals are durable and can have a lifetime of years of use.

4. Theory of Operation

Manufacturing tolerances - the fact that no two manufactured articles are ever EXACTLY the same - are present in all products, including every air rifle. Such physical differences may be small, just a few thousandths of an inch, but they can have a big impact on performance. These Archer Airguns XMV Tune Kits improve the



performance of the Ruger Air Hawk and Blackhawk air rifles by overcoming manufacturing tolerances in two ways in the area of the breech seal.

The breech seal fits into a circular slot machined into the rear face of the barrel. Manufacturing tolerances mean that the depth of this slot is slightly different between individual air rifles. The average depth of this slot is 95 thou - but it varies between 86 thou and 103 thou in the 37 guns measured - a variation of 17 thousandths of an inch.

The high precision shims provided in the XMV Tune Kits allow the depth of the slot to be built up to a precise, uniform depth. This is important because the breech seal compressed against the bottom of the slot (or the shims in it) when the air rifle is fired.

The variability of the breech seal slot depth is further compounded by a similar variability in the thickness of the factory breech seals. The breech seals found on the Ruger Air Hawk and Blackhawk average 95 thou thick, but the maximum thickness is 103 thou and the minimum 93 thou. Thatʼs a variability of 10 thousandths of an inch. Combined with the variability in slot depth, thereʼs much potential for breech seal projection to be imperfect and muzzle velocity to be reduced as a result.

The breech seal is also compressed against the front of the gunʼs compression chamber. As the compression chamber and barrel do not meet exactly (by design), the breech seal is designed to project beyond the rear of the barrel and seal the gap when the gun is fired. If the breech seal does not project sufficiently, air is lost when the gun is fired and that results in lower muzzle velocity.

As you can see from the table on the next page, the average breech seal projection of these guns is only 0.3 thou. From experimentation, we find that the projection required to maximize muzzle velocity is about 14 - 16 thou. Interestingly, a very similar projection as is found in a sample RWS 34 (a very similar design) and the Beeman 1073 (a different design but using a similar breech seal concept and a strong shooter).



All measurements in thousandths of an inchAll measurements in thousandths of an inchAll measurements in thousandths of an inch Factory Breech Seal Thickness

Slot Depth Factory Shim

Thickness

Projection of Factory

Breech Seal

Ruger Air Hawk/Blackhawk sampleRuger Air Hawk/Blackhawk sample .177 Cal 95 103 0 -8

XS25 sample XS25 sample .22 Cal 93 97 0 -4

Ruger/Xisico Average (over 37 guns) Ruger/Xisico Average (over 37 guns) Ruger/Xisico Average (over 37 guns) 95.4 95.1 0 0.3

RWS 34 sample RWS 34 sample .22 Cal 91 87 10 14

Beeman 1073 Average (over 5 guns)Beeman 1073 Average (over 5 guns)Beeman 1073 Average (over 5 guns) 71.6 57.8 0 13.8

These Archer Airguns XMV Tune Kits allow you to achieve the optimum breech seal projection for maximum muzzle velocity.

For consistency, detailed shooting tests were conducted on one Ruger Air Hawk (serial number 00190828) and one Xisico XS25 (serial number 111128342, a very similar air rifle but in .22 caliber). Further testing on other examples of the same guns, together with an RWS/Diana 34 (note that the Diana factory DOES shim these guns), validated these test results.

The sample Ruger and Xisico guns tested showed that - in factory condition - the breech seals of these guns did not project at all from the rear of the barrel. The result was a loss of muzzle velocity that these Archer Airguns XMV Tune Kits enables us to recover.

The diagrams on this page show how the breech seal can be below the surface of the barrel in many cases and how placing a shim under the breech seal provides the required projection to avoid muzzle velocity loss.



5. Donʼt shim too much!

Note that there is a point at which increasing breech seal projection does not increase muzzle velocity any further. The only effect is likely to be inaccuracy. This peaking of fps is clearly shown in the following graph of testing a Ruger Air Hawk in .177 caliber with 8.56 Grain Stoeger X-Field pellets.

Muzzle velocity peaked at 864fps with 20 thou or greater breech seal projection using the original factory breech seal. But vertical stringing took place at above 15 thou projection, making 849fps the maximum practical muzzle velocity attainable before replacing the factory breech seal and using lighter Stoeger X-Speed pellets.

As you can see, the tested gun had negative breech seal projection of 8 thou in factory condition! Much muzzle velocity was being lost due to the complete lack of breech seal projection, but the gun still shot accurately.

The bars in the graph plots the increase in fps (Y - vertical - axis) against the breech seal projection (X - horizontal - axis) for the factory breech seal with increasing shim thicknesses.



If you see a significant drop in the point of impact of the same type of pellets fired with your air rifle after installing shim(s) and the new breech seal, the amount of shimming needs to be reduced. This is also true if your gun produces vertical “stringing” of the shots, as shown in the targets below.

Thereʼs no point in a small further increase in muzzle velocity if accuracy is not maintained!

6. So how do I know if these XMV Tune Kits will improve the muzzle velocity of my air rifle?

Thereʼs a simple test to help you decide if your air rifle can benefit from an XMV Tune Kit.

SAFETY FIRST, CHECK THAT YOUR AIR RIFLE IS NOT LOADED OR COCKED BEFORE PROCEEDING!

Simply break open the barrel of the gun and hold it securely and fully open. Then take a ruler (or other straight edge) and slide it carefully across the rear of the barrel, making sure to pass over the breech seal.

1. If the ruler slides straight across and you feel no resistance or “catching” on the breech seal, then the breech seal is too low in the slot. Your air rifle is definitely losing significant muzzle velocity: you will gain maximum benefit from an XMV Tune Kit.



Above. Holding the gun safely with the barrel “broken”.

2. If the ruler just catches or “drags” a little on the breech seal, the seal is projecting but only a little - probably between just 1 and 5 thou. Your air rifle is losing some muzzle velocity and will still benefit from a tune kit.

3. If you can feel a definite bump then the seal is projecting somewhere around 10 thou or more. This means that shimming with the XMV Tune Kit will not produce a significant increase in muzzle velocity, but you may gain an improvement with the high durometer breech seal. You will definitely gain hundreds of fps in muzzle velocity by using Stoeger X-Speed pellets.



Above. Testing breech seal projection with a ruler. Note that the barrel has been removed from the gun for clarity in illustration.

After conducting this test, you will need to load a pellet and fire it safely, as the gun will have been cocked when breaking the barrel for the test.

The results of this ruler test indicate the number of shims that should be used with a new seal to achieve maximum muzzle velocity, as shown in the following table.

Ruler Test Results Number of Shims

No resistance Start with 2 shims, may require 3 shims plus new breech seal

Just catches 1 shim plus new breech seal

Definite bump New breech seal only, no shim



NOTE: IF TOO MANY SHIMS ARE USED, ACCURACY MAY SUFFER AND MUZZLE VELOCITY WILL NOT INCREASE FURTHER. START WITH THE RECOMMENDED NUMBER OF SHIMS ONLY!

7. Installation steps.

AGAIN, SAFETY FIRST, ENSURE THAT YOUR AIR RIFLE IS NOT COCKED OR LOADED BEFORE PROCEEDING!

Although installation can be undertaken by one person, itʼs easier and safer for one person to hold the gun while another replaces the breech seal and shims.

1. Repeat the “ruler test” described above (if necessary). This will give a good idea for the depth of shims to be installed.

2. Then use a small, thin probe - such as a domestic dressmaking pin, eyeglasses screwdriver or O ring pick - and carefully slide it between the outside of the factory breech seal and the barrel slot. Lever the breech seal out.

3. Now take the number of precision steel shims to match the results of the ruler test and drop them into the annular slot revealed by removing the factory breech seal. Ensure that the shim(s) are flat and level on the floor of the slot.

4. Then take a new, high durometer breech seal and push this into the slot, on top of the shims. Use finger pressure to ensure that the new seal is fully engaged in the slot. Try the ruler test again to confirm that the new breech seal causes a definite bump to the ruler.

5. After installing the new breech seal and shims, test fire the gun 5 times safely at a paper target with the pellets you normally use. There should be very little change in the point of impact of the pellets on the target, compared to before fitting the replacement parts.

6. Now, carefully remove the breech seal and add one more shim. Then replace the breech seal. Test again. If the point of impact is still in about the same place, this is the maximum increase in muzzle velocity available for your gun.

7. But if either the point of impact is now much lower than before, or, the target shows unusual vertical “stringing” of pellet holes, then the thickness of shims is too great. Repeat the steps above, this time removing one of the shims before replacing the breech seal. Re-test. The point of impact should now be back close to its original location. Now you have gained the maximum increase in muzzle velocity available for your gun.



8. Note that - because they shoot so fast - the Stoeger X-Speed pellets will almost certainly have a different point of impact to that of the pellets you have previously used. You will need to adjust the elevation and windage of your scope slightly to remain on target when using these new pellets. (This applies, of course, when any change of pellets is made).

Now back to our test target. This test shows that the X-Speed pellets are accurate too and have excellent consistency (standard deviation). That targetʼs about as good as I can achieve from a spring air rifle and itʼs a huge improvement on the original factory muzzle velocity!



8. Test Results for .22 Caliber Xisico XS25 Air Rifle

The results for this air rifle showed less improvement due to shimming than the Ruger Air Hawk. But more improvement resulted from using the high durometer breech seals and a huge improvement in muzzle energy was achieved when using the lighter pellets.

Overall, itʼs clear that installing the XMV Tune Kit improved the muzzle velocity of this air rifle by 36fps, and that shooting Stoeger X-Speed pellets raised that increase in muzzle velocity to 246fps above that of the gun in factory condition. Thatʼs an increase in muzzle energy of a huge 40%!

Xisico XS25 Condition (gun was fired sufficiently to eliminate dieseling before testing started)

Tested Pellets

Seal Projection

(thou)

Muzzle Velocity

(fps)

Muzzle Velocity Increase

Over Factory

Condition

Muzzle Energy (ft/lbs)

Muzzle Energy

Increase Over

Factory Condition

“Out of the box” from factory The Peak

Domes 14.12 Grain

-4 631 N/a 12.6 N/a

Factory breech seal with optimum shim thickness

The Peak

Domes 14.12 Grain

16 652 22 13.3 5%

Replacement breech seal with optimum shim thickness (Archer Airguns XMV Tune Kit)

The Peak

Domes 14.12 Grain

16 668 36 14.0 10%

Replacement breech seal with optimum shim thickness and lighter pellets (Archer Airguns XMV Tune and Pellet Kit)

Stoeger X-Speed

5.66 Grain

16 878 246 17.6 40%

As with the Ruger Air Hawk, the Xisico XS25 air rifle showed a significant increase in muzzle velocity when the XMV Tune Kit was installed. Again, also using the Stoeger X-Speed pellets included in the Archer Airguns XMV Tune and Pellet Kit resulted in a huge increase in both muzzle velocity and muzzle energy from this air rifle!



archer airguns xmv tune kit for ruger

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