MILSTD1913

MIL-STD-1913 is a United States military standard that specifies the design and mounting parameters for accessory rails used on firearms and related equipment. It is widely known as the Picatinny rail, a name derived from the Picatinny Arsenal where the standard was developed. The standard defines the geometry, dimensions, tolerances, and mounting interfaces that enable interchangeable accessories such as sights, grips, bipods, lasers, and lights to be attached to weapons across manufacturers.

The standard emerged to provide a uniform, repeatable mounting platform and supersede older, nonstandard systems such as the Weaver rail. It establishes a repeating slot pattern along a straight rail, along with corresponding mounting features on accessories, so that sights and other devices can be aligned consistently and retained securely under operational conditions.

MIL-STD-1913 is widely adopted by the U.S. military and has influenced NATO and allied forces as well as civilian firearms markets. The core concept is a universal, standardized interface that supports quick attachment and high repeatability of accessory alignment, while allowing for a range of rail lengths and heights to accommodate different weapon platforms.

Variations and related standards exist for different applications, but the defining principle remains the same: a common mounting rail system that enables interchangeable accessories to be mounted on firearms with predictable positioning and stability.

See also: Weaver rail, Picatinny rail, NATO accessory mounting standards.