United States Department of Defense - M110 Semi-Automatic Sniper System

The M110 Semi-Automatic Sniper System (or M110 SASS) is a semi-automatic rifle that is chambered for the 7.62x51mm NATO round, developed by the American firearm manufacturer Knight's Armament Company.

The M110 Semi-Automatic Sniper System is intended to replace the M24 Sniper Weapon System and M21 Sniper Weapon System used by snipers, spotters, designated marksmen, or squad advanced marksmen in the United States Army. The U.S. Army ran a competition involving several designs, including ones from Knight's Armament Company, Remington, and DPMS Panther Arms. It is interesting to note that all the entries from these companies seemed to use designs based around the AR-10 action. On September 28, 2005, the Knight's Armament Co. rifle won the competition and was selected to be the M110 Semi-Automatic Sniper System. In April 2007, U.S. Army soldiers from Task Force Fury in Afghanistan were the first in a combat zone to receive the M110.

The rifle was previously known as the XM110, but the U.S. Army has dropped its experimental status. It is manufactured by Knight's Armament Company in Titusville, Florida, though the complete system incorporates a Leupold daytime optic, Harris swivel bipod, AN/PVS-14 night sight and PALs magazine pouches of yet unpublished origin. The company name for the rifle is SR-M110 SASS, but the U.S. Army official designation is the M110 SASS. 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 and Mk 11 Mod 0 semi-automatic precision rifles, but differs significantly in buttstock and rail system design. The SR-25, Mk 11 Mod 0, and M110 are based loosely off the original AR-10 developed by Eugene Stoner but feature additional refinements instituted by KAC to maximize parts commonality with the AR15 / M16, improve weapon reliability, and increase accuracy.

The main differences between the Mk 11 Mod 0 and M110 are:

* 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 back-up iron sight (BUIS).
* 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 Mod 0.
* The M110's use of KAC's one-piece 30 mm scope mount instead of two separate scope rings.

Other changes were made when the XM110 made the transition to the M110. Features added were a buttstock hand-tightening knob, sling swivel sockets, a double sided bolt catch, and a button on the folding front sight to allow it to be locked into position.