What Is a Picatinny Gun Sight Mount?

The Picatinny rail is a mounting system used to attach optics or other accessories to firearms that adheres to a set of standard dimensions.

  1. Name

    • The Picatinny rail is named for the Picatinny Arsenal, the U.S. military armaments facility where it underwent trials. This facility is located in Morris County, New Jersey, 45 miles west of New York City.

    Design

    • A standardized version of the Weaver rail, the Picatinny rail is a dovetail or T-shaped mount with diagonal grooves that prevent the mounted accessory from moving back and forth due to recoil. Also known as the Swan/Weaver rail, it was patented by Dick Swan in 1989.

    Applications

    • Originally used as a scope mount, attached directly to a weapon's receiver, the Picatinny rail can now be found on stocks and forends in a variety of configurations as an attachment point for sighting and support systems, as well as bayonets and grenade launchers.

    Adoption by the U.S. and NATO

    • The U.S. military adopted this accessory mounting rail on Feb. 3, 1995, where it is officially known as MIL-STD-1913. NATO soon followed suit and designated it STANAG 2324.

    Weaver Mount Compatability

    • Accessories designed for Weaver mounts will usually fit on Picatinny rails. Due to its precise dimensions and larger grooves, accessories designed to be mounted on Picatinny rails seldom fit on Weaver mounts.