Picatinny rail

The Picatinny rail (MIL-STD-1913 rail or 1913 rail) is an American rail integration system designed by Richard Swan that provides a mounting platform for firearm accessories. It forms part of the NATO standard STANAG 2324 rail. It was originally used for mounting of telescopic sights atop the receivers of larger caliber rifles.

Once established as United States Military Standard, its use expanded to also attaching other accessories, such as: iron sights, tactical lights, laser sights, night-vision devices, reflex sights, holographic sights, foregrips, bipods, slings and bayonets.

An updated version of the rail is adopted as a NATO standard as the STANAG 4694 NATO Accessory Rail.

Attempts to standardize the Weaver rail mount designs date from work by the A.R.M.S. company and Richard Swanson in the early 1980s.^{[citation needed]} Specifications for the M16A2E4 rifle and the M4E1 carbine received type classification generic in December 1994.^{[citation needed]} These were the M16A2 and the M4 modified with new upper receivers where rails replaced hand guards. ^{[verification needed]}

The MIL-STD-1913 rail is commonly called the "Picatinny Rail", in reference to the Picatinny Arsenal in New Jersey. Picatinny Arsenal works as a contracting office for small arms design (they contracted engineers to work on the M4).

Picatinny Arsenal requested Swan's help in developing the rail, but did not draft blueprints or request paperwork for a patent. That credit goes to Richard Swanson of A.R.M.S., who conducted research and development and acquired a patent for the rail in 1995. Swan has litigated in civil court against Colt and Troy industries regarding patent infringement. The courts found that Troy had developed rifles with rail mounting systems nearly identical to the MIL-STD-1913 rail.

A metric-upgraded version of the 1913 rail, the STANAG 4694 NATO Accessory Rail, was designed in conjunction with weapon manufacturers like Aimpoint, Beretta, Colt, FN Herstal and Heckler & Koch, and was approved by the NATO Army Armaments Group (NAAG), Land Capability Group 1 Dismounted Soldier (LCG1-DS) on May 8, 2009.

Many firearm manufacturers include a MIL-STD-1913 rail system from the factory, such as the Ruger Mini-14 Ranch Rifle.