8/2/2019 Picatinny Rails, Weaver Rails, Whats The Difference

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http://www.brownells.com/.aspx/lid=12631/GunTechdetail/Picatinny-Rails-Weaver-Rails-What-s-The-Difference

Picatinny Rails, Weaver Rails, Whats The

Difference?

When you are looking through the Brownells Catalog, there are many different parts and accessories thatuse the words Picatinny and Weaver to describe what they are compatible with. Just what is a Picatinny

Rail anyway? And how is it different from a Weaver? It will be beneficial to look at the origin of the

Picatinny system first.

The Picatinny Rail is a term that has evolved in the firearm industry from a military standard, specifically

MIL-STD-1913 (AR) which was adopted on February 3, 1995. The title of the publication is

Dimensioning Of Accessory Mounting Rail For Small Arms Weapons and this document specifiedexactly what the dimensions and tolerances were for any mounting systems that were to be submitted for

acceptance by the military. The term Picatinny comes from the place of origin for this system, the

Picatinny Arsenal located in New Jersey. MIL-STD-1913 specifies the dimensions required forconsideration, including length, width, height, and angles and the tolerances allowed for each measurement.

The key distinction of the MIL-STD-1913 lies in the specification for the profile and the recoil groove.

Source: MIL-STD-1913 (AR) 3 February 1995

Source: MIL-STD-1913 (AR) 3 February 1995

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8/2/2019 Picatinny Rails, Weaver Rails, Whats The Difference

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What are the differences between the Picatinny and the Weaver systems? The profile of the twosystems is virtually identical. Depending on the quality of the machining done by the manufacturer, the two

systems should be indistinguishable from the profile. The key difference lies in the placement of the recoil

grooves and with width of the grooves. MIL-STD-1913 (Picatinny) grooves are .206 wide and have acenter-to-center width of .394. The placement of these grooves has to be consistent in order for it to be a

true Picatinny MIL-STD system. Weaver systems have a .180 width of recoil groove and are not

necessarily consistent in a center-to-center measurement from one groove to the next. In many instances, a

Weaver system has a specific application that it is machined for, so interchangeability is not necessarily anissue. A MIL-STD-1913 system must adhere to the specifications listed above in order for it to be

considered MIL-STD, since the military desires uniformity in the recoil grooves to allow for different

systems to be mounted on the weapon with no concern for compatibility.

Now, what does this mean to you? Boiled down, it means that accessories designed for a Weaver system

will, in most cases, fit on a Picatinny system. The reverse, however, is probably not the case. Due to thelarger recoil groove, Picatinny accessories will not fit a Weaver system. There are, of course, exceptions

to every rule, but for a good rule-of-thumb, Picatinny wont fit Weaver, but Weaver will fit

Picatinny.