The M110 Semi Automatic Sniper System (M110 SASS) is an American semi-automatic precision rifle that is chambered for the 7.62×51mm NATO round. It is manufactured by Knight’s Armament Company, developed from the Knight’s Armament Company SR-25, and adopted by the U.S. military following the 2005 US Army Semi-Automatic Sniper Rifle (XM110 SASR) competition. The M110 is to be replaced by the lighter and more compact M110A1 CSASS, which is developed from the G28, a variant of the Heckler & Koch HK417.
The M110 Semi-Automatic Sniper System is intended to replace the M24 Sniper Weapon System used by snipers, spotters, designated marksmen, or squad advanced marksmen in the United States Army. However, the U.S. Army still acquired M24s from Remington until February 2010. After witnessing the effects of USSOCOM snipers and extensive after-action reports from SOF snipers throughout the Iraqi theater of operations, the U.S. Army ran a competition involving several designs, including rifles from Knight’s Armament Company, Remington, and DPMS Panther Arms. On September 28, 2005, the Knight’s Armament Co. rifle won the competition and was selected to be the supplier of the M110 Semi-Automatic Sniper System. The XM110 underwent final operational testing in May and June 2007 at Fort Drum, New York by a mix of Special Forces troops and Sniper trained soldiers from the 10th Mountain Division. In April 2008, U.S. Army soldiers from Task Force Fury in Afghanistan were the first in a combat zone to receive the M110. The troops rated the weapon very highly, noting the quality of the weapon and its semi-automatic capabilities compared to the bolt-action M24. The United States Marine Corps will also be adopting the M110 to replace some M39 and all Mk 11 as a complement to the M40A5. It is manufactured by Knight’s Armament Company in Titusville, Florida, though the complete system incorporates a Leupold 3.5–10× variable power daytime optic, Harris swivel bipod, AN/PVS-26 or AN/PVS-10 night sight and PALs magazine pouches of yet unpublished origin. The rifle has ambidextrous features such as a double-sided magazine release, safety selector switch, and bolt catch.
The rifle is similar to the SR-25/Mk 11 Mod 0, but differs significantly in buttstock and rail system design. The SR-25, Mk 11 Mod 0, and M110 are based loosely on the original AR-10 developed by Eugene Stoner but feature additional refinements instituted by KAC to maximize parts commonality with the AR-15 design, improve weapon reliability, and increase accuracy.
The main differences between the Mk 11 and M110 are improvements suggested by a user group meeting between NAVSPECWAR, USASOC and USA in 2007:
- The rail system used: the KAC Free Floated RAS on the Mk 11 is replaced by a URX modular rail system with integral folding front 600-meter backup iron sight.
- The M110 buttstock: fixed, though the buttplate is adjustable for length of pull to match user preferences. Adjustment can be made without tools via a notched hand-tightened knob on the right-hand side of the stock. This feature was added during the change from XM110 to M110. The fixed buttstock also features integral quick-detachable sling swivel sockets located on each side of the stock near the rear of the lower receiver.
- The addition of a flash hider to the barrel of the M110, which also necessitates a modified QD Suppressor unit similar to that on the Mk 11.
- The M110’s use of KAC’s one-piece 30 mm scope mount instead of two separate scope rings.
On June 12, 2008, the M110 was ranked #2 on the U.S. Army’s top ten inventions of 2007.
According to performance specification (MIL-PRF-32316 (AR) w/AMENDMENT 1, 5 October 2009):
188.8.131.52.1 Accuracy. The distance between the mean point of impact of each shot group, both unsuppressed and suppressed, shall be not greater than 1.1 inches at 300 feet.
184.108.40.206.2 Dispersion. The average mean radius (AMR) (see 6.11), of each shot group shall be not greater than to 0.68 inches at 300 feet. All targets shall be fired on using M118LR ammunition or equivalent, using five (5) round groups.
|Mass||6.27 kg (13.84 lb) (unloaded)|
|Length||1,029 mm (40.5 in) (buttstock fully retracted)
1,181 mm (46.5 in) (buttstock fully retracted and suppressor attached)
|Barrel length||508 mm (20 in)|
|Cartridge||7.62×51mm NATO, 6.5mm Creedmoor|
|Action||Gas-operated, rotating bolt|
|Rate of fire||Semi-automatic|
|Muzzle velocity||783 m/s (2,570 ft/s) with 175 gr. M118LR|
|Effective firing range||800 metres (875 yd) (point targets)|
|Feed system||10 or 20-round detachable SR-25 pattern box magazine|