Engineering:Rail Integration System

KeyMod and M-LOK handguards from various manufacturers. The tops of these handguards feature Picatinny rails. These handguards were used in a KeyMod™ vs. M-LOK™ Modular Rail System comparison in 2017 by the US Naval Surface Warfare Center Crane Division.

Rail interface system or rail integration system (RIS for short, sometimes also referred to as rail accessory system, RAS) is a generic term for a standardized rail system for attaching accessories to small firearms such as pistols, rifles and light machine guns. Such accessories commonly include tactical lights, laser aiming modules, forward hand grips for improving weapon handling, telescopic sights for long-range targets, and reflex sights/red-dot sights for short/medium-ranged targets, back-up iron sight, bipods/tripods, and bayonets.

Type

Most RIS equipment is compatible with one or more of the most common rail systems, all of which are broadly similar:

• Dovetail rail — one of the earliest rail system, relies primarily on friction from side unit set screw on the mounted accessory to stop longitudinal shifting
  • Warsaw Pact rail — a Soviet-designed dovetail rail variant with cut-outs that allows quick side-mounting of optics (e.g. PSO-1 and USP-1) on Dragunov sniper rifles, RPG-7 and RPG-29 grenade launchers, as well as some versions of AKM and AK-74 assault rifles and PK family machine guns.
• Weaver rail mount — an early improvement design upon the dovetail rail invented by William Ralph Weaver (1905–1975), still popular in the civilian market
• Picatinny rail — also known as the Pic rail, MIL-STD-1913 rail or STANAG 2324 rail (canceled), the mil-spec standardized rail system evolved from the Weaver rail
• NATO Accessory Rail — also known as the STANAG 4694 rail, a metric standardized upgrade from the Picatinny rail
• Keymod — open source "negative space" (hollow slot) design introduced by VLTOR to replace the Picatinny rail for mounting accessories (except for scope mounts)
• M-LOK — a free licensed "negative space" design introduced by Magpul Industries to compete with KeyMod

These are used primarily in the military and by firearm enthusiasts to improve the usability of the weapon, being accessorized quickly and efficiently without requiring the operator to field-strip the weapon. Basic systems such as small rails (20mm is standard) with holes machined in them to be screwed onto the existing hand-guard of a rifle and can cost as little as US$25 to US$40. More advanced systems allow for numerous accessories to be mounted simultaneously and can cost upwards of US$200.

See also

• UIT rail, an older standard used for mounting slings particularly on competition firearms
• Sling swivel, older standard used for mounting slings, particularly on hunting firearms
• Zeiss rail, a ringless telescopic sight mounting standard introduced by Carl Zeiss AG

External links

• KeyMod vs. M-LOK comparison
• KeyMod Rail Integrated System release by Military times
• MAgpul FAQ pdf on MLok rain Integration System
• KeyMod vs. M-Lok: The Next AR Rail Standard by Chris Baker, November 19, 2014
• Naval Special Warfare Center Crane Division report on 2 Modular Rail Integrated Systems
• KeyMod VS MLok Comparison 2014
• M-LOK vs KeyMod comparison 2017 MLok and KeyMod Comparison 3 years later 2017