United States Army Squad Designated Marksman Rifle +Search for Videos

refimprove|date=March 2013
name=US Army SDM-R
Soldiers from the 3rd Infantry Division+ with SDM rifles.
United States+
Designated marksman rifle+
Operation Enduring Freedom+, Operation Iraqi Freedom+
5.56×45mm NATO+
Gas-operated+ (direct impingement+)

with optic and fully loaded 30-round magazine

20- or 30-round detachable box magazine+

The '''United States Army Squad Designated Marksman Rifle''' ('''SDM-R''') is a heavily modified M16+-series semi-automatic rifle+ intended to provide increased accuracy at longer ranges, giving infantry+ squad+s greater firepower.

The addition of an embedded marksman+ at the platoon+ or squad+ level has been a continuing process in the U.S. military+. The U.S. Marine Corps+ (USMC) experimented with this during ''Project Metropolis'', before creating the "Squad Advanced Marksman" (SAM) position along with the Squad Advanced Marksman Rifle+ (SAM-R) specifically for this purpose.

The 3rd Infantry Division 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 SDM is an integral part of the squad and serves as a rifleman+ first and designated marksman+ second. The SDM is not meant to be a squad sniper+ who engages the enemy with precision fire at extreme ranges, but instead is trained to directly support the squad with well-aimed shots at ranges slightly beyond the normal engagement distances for riflemen.

Much like the U.S. Marine Corps SAM-R, the 3rd Infantry division SDM-R was an accurized+ M16 rifle+ (5.56×45mm NATO+ caliber) built in-house by the U.S. Army Advanced Marksmanship Unit, and was informally known as "the AMU rifle". SDM-R's have only been built for one major Army division and is not an Army program of record. 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+ that led to the development of weapons such as the United States Navy Mark 12 Mod X Special Purpose Rifle+ (SPR) and the SEAL Recon Rifle+.

The National Guard Marksmanship Training Center of the Arkansas Army National Guard+ conducts the fourteen-day-long Squad Designated Marksman Course at Camp Joseph T. Robinson. Soldiers fire over 1500-rounds from the M16A4 rifle under the close supervision of course cadre.

Task Force Small Arms Readiness Group (TF SARG) conducts the week-long SDM course at the SARG academy at Camp Bullis+, Texas+. Many of the instructors are President's 100+ recipients.

*'''Upper and lower receivers:''' The rifles were produced by the Army Marksmanship Unit+ (AMU) at Fort Benning+, Georgia using either new semi-automatic ArmaLite+ lower receivers+ or existing Army M16A2 or A4 lower receivers previously supplied by either Colt+ or Fabrique Nationale de Herstal+. All rifles were equipped with a fixed A2 stock+ and a Knight's Armament Company+ 2-stage match grade+ trigger capable of only semi-automatic+ fire. The upper receivers were flat-top style, but unlike the SAM-R and SPR, they did not have extended feed ramps.
*'''Barrel:''' The 1:7 twist+, barrel+ from the M16A2 and A4 were replaced with a stainless steel+ Douglas Barrels 1:8 twist, 20-inch barrel, with 12 flutes cut into the barrel to reduce weight. The front sight block was installed with 4 set screws instead of two taper pins. The SDM-R retained the A2-style flash hider+.
*'''Sights and optics:''' The issued optic+ was a 4×32 Advanced Combat Optical Gunsight+ (ACOG) (models TA31F, TA31RCO, TA01, TA01B, or TA01NSN). A Matech Industries 600-meter backup iron sight+ was also used.
*'''Handguard:''' Daniel Defense M4 Rail 12.0 handguard, with an octagonal aluminum collar locking it to the upper receiver. The handguard provides a free-floating Picatinny rail+ forend.
*'''Bipod:''' A Harris S-L bipod+ attached to an ARMS #17 throw-lever rail mount was mounted to the underside of the handguard. Since the handguard was free-floating, it did not come into contact with the barrel, and any pressure from the bipod on the handguard did not deflect the barrel.

The 82nd Airborne Division+ examined an alternate version, based on the M4 carbine+. The barrel was to have been an long fluted+ Douglas barrel with 1:8 twist. A mid-length gas system was to be used, along with the Daniel Defense M4Rail 9.0 handguard. This effort never went beyond the staffing process.

* Tabuk Sniper Rifle+
* United States Marine Corps Squad Advanced Marksman Rifle+
* United States Marine Corps Designated Marksman Rifle+
* SEAL Recon Rifle+
* United States Navy Mark 12 Mod X Special Purpose Rifle+
* List of individual weapons of the U.S. Armed Forces+
* Designated marksman+
* Civilian Marksmanship Program+



AR-15 variants:

United States Army Squad Designated Marksman Rifle+ The United States Army Squad Designated Marksman Rifle (SDM-R) is a heavily modified M16-series semi-automatic rifle intended to provide increased accuracy at longer ranges, giving infantry squads greater firepower.