NATO Accessory Rail
The NATO Accessory Rail (or NAR), defined by NATO Standardization Agreement (STANAG) 4694, is a rail interface system standard for mounting accessory equipments such as telescopic sights, tactical lights, laser aiming modules, night vision devices, reflex sights, foregrips, bipods and bayonets to small arms such as rifles and pistols.
The NATO Accessory Rail is backwards-compatible with the STANAG 2324/MIL-STD 1913 Picatinny rail, which dates back to 3 February 1995, and was designed in conjunction with weapon specialists like Aimpoint, Beretta, Colt Firearms, FN Herstal and Heckler & Koch. The Heckler & Koch G28 designated marksman rifle features NATO Accessory Rails.
According to the NATO Army Armaments Group the differences between the MIL-STD 1913 Picatinny rail and the STANAG 4694 are:
- A metric reference drawing.
- Additional new measurements and tolerances.
- Adjustments of some measurements.
- Tighter straightness tolerances (approximately 50%).
Another notable change is the recommendation that while in the Picatinny rail system the V-angles are used for the alignment and reference of the accessory, NATO recommends using the top surface instead. Initial NATO tests had shown that the Picatinny rail system did not provide good repeatability. Using the top surface as a reference and alignment of the grabbers provided excellent repeatability.
NATO rail design is also used for small video camera setups. Videos shot with DSLR or Mirrorless cameras use a variety of mounting systems for attaching microphones, monitors, lighting, and other accessories. A NATO-compatible rail is one of these systems. Although it is advertised to meet the same specifications, there is some discussion that some of the rails and accessories are not compatible with one another.
This section is missing information about STANAG 4740/AEP-90; see also original Tworx implementation. (October 2021)
Further plans are underway to develop a NATO standard to provide electrical power to rail mounted accessories in the future. Currently, Wilcox Industries, in cooperation with Surefire, is working on the creation of a railed forend for an AR-15 that will power battery-reliant accessories such as tactical lights and laser sights. Accessories are intended to be powered by one central battery pack or via their proprietary vertical grip, the Universal Control Grip.
- Rail Integration System, generic term for a system for attaching accessories to small firearms
- Weaver rail mount, early system used for scope mounts, still has some popularity in the civilian market
- Picatinny rail (MIL-STD-1913), improved and standardized version of the Weaver mount. Used for both for scope mounts, and for accessories (such as extra sling mounts, vertical grips, bipods etc.) Major popularity in the civilian market.
- Warsaw Pact rail, is a rail mount system to connect telescopic sights to rifles
- UIT rail, an older standard used for mounting slings particularly on competition firearms
- KeyMod - open standard design to replace MIL-STD-1913 for mounting accessories (except for scope mounts)
- M-LOK - free licensed competing standard to KeyMod
- Zeiss rail, a ringless scope mounting standard
- Weapons & Sensors, NATO Army Armaments Group
- NATO countries finalise plans for a standard rail adaptor system
- "NATO - STANAG 4694 - NATO ACCESSORY RAIL". standards.globalspec.com. Retrieved 2022-03-17.
- Military Standard 1913 - Dimensioning of accessory mounting rail for small arms weapons Archived 2010-11-26 at the Wayback Machine
- Heckler & Koch G28
- Thomas, Mitch. "PICATINNY AND NATO RAILS - GD&T". Thomas Mechanical Design - The Mitch Blog. Thomas Mechanical Design. Retrieved 8 January 2021.
- March, Sol. "DITCH THE CAGE WITH SMALLRIG'S SHOE-MOUNTED NATO RAIL". Suggestion of Motion Blog. Suggestion of Motion. Retrieved 8 January 2021.
- Powered Rail Presentation to Intl Infantry & Joint Service Small Arms System Symposium, May 20, 2009 Archived September 24, 2015, at the Wayback Machine
- Wilcox Industries Develops a "Power Rail" For ARs