United States Army Squad Designated Marksman Rifle
The United States Army Squad Designated Marksman Rifle (SDM-R) is a M16-series rifle modified to provide increased accuracy over range, giving infantry squads greater firepower.
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Background
The desire to have an embedded marksman at the platoon or squad level seems to be something appearing across the board in the US Military. The United States Marine Corp experimented heavily with this during Project Metropolis, before creating the Squad Advanced Marksman position and creating a rifle specifically for them. The US Army has followed suit in implementing a training program to have one marksman per squad, the Squad Designated Marksman (SDM), and developing a rifle, the Squad Designated Marksman Rifle (SDM-R). The Squad Designated Marksman is an integral part of the squad and serves as rifleman first and designated marksman second. The SDM is not meant to be a squad sniper that engages with precision fire at extreme ranges. Instead, the soldier is trained to directly support the squad with well-aimed shots at ranges slightly beyond the normal engagement distances for riflemen.
Much like the USMC's Squad Advanced Marksman Rifle (SAM-R), the SDM-R is an accurized AR15/M16 type rifle built in-house by the U.S. Army Marksmanship Unit (USAMU; this rifle is also know informally as 'the AMU rifle'). The SDM-R is designed to provide engagement capability at the squad level to 600 meters, similar to the needs expressed by members of USSOCOM and the USMC that led to the development of weapons like the Mk 12 Mod 0/1, the SEAL's 'Recon Rifle', and the USMC SAM-R.
Specifications
- Upper & Lower Receivers: From most reports the rifles appear to have been built up using existing lower receivers in inventory. What this means is the rifles are completed using A2/A4 lowers previously supplied by either Colt or Fabrique National, with a fixed A2 stock. The upper receivers are flat top style. Unlike the SAM-R and SPR, it does not have extended feed ramps. The trigger has been replaced with a Knight's Armament Company 2-stage match trigger capable of only semiautomatic fire.
- Barrel: The traditional 1:7 twist 20-inch barrel has been replaced with a stainless steel Douglas 1:8 twist 20" barrel, with fluting to reduce weight. The front sight block is installed with 4 set screws instead of two taper pins. The A2 style flash hider is retained.
- Sights & Optics: In one of the few photos of the completed SDM-R, the rifle is shown to be fitted with a Trijicon ACOG medium range optic, but there is the undoubted possibility that longer range optics have also been fitted. These rifles have apparently all been fitted with a Matech Industries 600-meter backup iron sight.
- Handguard: The SDM-R uses a Daniel Defense M4Rail 12.0 handguard, with an octagonal steel collar locking it to the receiver block. The Daniel Defense handguard provides a free-floating MIL-STD-1913 rail forend.
Variants
The 82nd Airborne Division uses an alternate version, based on the M4 Carbine. The barrel is an 18"-long fluted Douglas barrel with 1:8 twist. A mid-length gas system is used, along with the Daniel Defense M4Rail 9.0 handguard.
See also
- U.S. Marine Corps Squad Advanced Marksman Rifle
- SEAL Recon Rifle
- United States Navy Mark 12 Mod 0 Special Purpose Rifle
- List of individual weapons of the U.S. Armed Forces
- Designated marksman