M110 Semi-Automatic Sniper System
The M110 Semi-Automatic Sniper System (SASS) is a lightweight, direct gas-operated, semi-automatic sniper rifle chambered in 7.62×51mm NATO, designed to engage personnel and light materiel targets at ranges up to 800 meters.[1][2] Manufactured by Knight's Armament Company as a variant of the SR-25 platform, it provides sniper teams with enhanced firepower through rapid semi-automatic fire while preserving the precision required for designated marksman roles in urban and close-combat scenarios.[2] Adopted by the U.S. Army following a 2005 competition won on September 28, the system was type-classified in 2007 and entered full production shortly thereafter.[2][3] Key features of the M110 include a 20-inch match-grade barrel with a 1:11 twist rate for optimal stability with 7.62mm ammunition, ambidextrous controls, a MIL-STD-1913 rail for mounting optics such as the 3.6-18× variable power scope, and a quick-detachable sound suppressor to reduce signature during operations.[1][2] It uses detachable 20-round magazines, weighs 13.7 pounds empty (increasing to 17.4 pounds with suppressor and optics), measures 40.5 inches in length (46.5 inches suppressed), and achieves sub-1.0 MOA accuracy with a barrel life exceeding 5,000 rounds.[1][2] The system also incorporates an M151 Spotting Scope (12-40× magnification) for target identification beyond 1,000 meters, along with a detachable bipod and a rugged Pelican transport case.[1] Developed as a non-developmental item to rapidly address the need for semi-automatic capability supplementing bolt-action rifles like the M24, the M110 was procured under an initial contract for up to 1,200 units and has been fielded to U.S. Army sniper teams, Marine Corps units, and special operations forces since 2008. As of 2025, additional units continue to be procured, including for international aid to Ukraine.[2][4] In 2008, it was recognized as one of the top ten inventions of 2007 by the U.S. Army for its impact on operational missions, enabling faster target engagement and improved survivability in dynamic combat environments.[3] The rifle's reliability—demonstrated by a 90% probability of functioning through 300 rounds without critical failure—has made it a staple for precision engagements, though ongoing modernization efforts have led to its partial replacement by more compact variants.[2]History and Development
Procurement and Origins
The U.S. Army identified a need to replace the bolt-action M24 Sniper Weapon System with a semi-automatic sniper rifle to facilitate faster follow-up shots, enhancing effectiveness in dynamic urban and counter-insurgency operations where multiple targets could emerge rapidly. This requirement stemmed from lessons learned during the Global War on Terror, emphasizing the limitations of bolt-action rifles in close-quarters engagements.[5] In December 2004, the U.S. Army Tank-automotive and Armaments Command at Picatinny Arsenal issued Request for Proposals (RFP) No. W15QKN-05-R-0433 for the Semi-Automatic Sniper System (SASS) program, seeking a precision 7.62×51mm NATO-chambered rifle capable of accurate fire out to 800 meters with rapid semi-automatic capability. Five manufacturers submitted proposals by the March 11, 2005, deadline, including Knight's Armament Company (KAC), Remington Arms Company, DPMS Panther Arms, and ArmaLite.[6] The evaluation prioritized bid sample performance and technical merit, with live-fire testing assessing accuracy, reliability, and suppressor integration; three proposals were initially excluded, leaving KAC and Remington in the competitive range. On September 28, 2005, following final revisions and a protest dismissal by the Government Accountability Office, KAC was awarded the initial contract valued at $16,561,656 for development and production of the XM110 SASS, based on a modified SR-25 design derived from the AR-10 platform and featuring the URX modular rail system for optics and accessories.[5] After the 2005 contract award, the system was designated XM110 during development and early deliveries, achieving type classification and redesignation as M110 in 2007. Developmental milestones included extensive government testing in 2006-2007, culminating in operational trials at Fort Drum, New York, involving Special Forces and conventional snipers to validate system performance under simulated combat conditions.[7] The rifle achieved type classification as the M110 in 2007, with initial deliveries to Army units commencing in 2007.[8]Initial Deployment
The U.S. Army officially adopted the M110 Semi-Automatic Sniper System (SASS) in 2007, marking the transition from its experimental XM110 designation following successful operational testing that included input from Special Forces troops.[9] Initial units were issued primarily to sniper teams within special operations forces and conventional Army elements, enabling rapid integration into forward-deployed roles. By this point, the system had undergone refinements to meet Army requirements, such as the inclusion of a quick-detach suppressor to mitigate blast and dust signatures in operational environments.[10] The first combat deployment of the system occurred in April 2007, when U.S. Army snipers from Task Force Fury received the XM110 at Forward Operating Base Salerno in Afghanistan, prior to its final designation as the M110.[8] This marked the system's debut in a combat zone, where it quickly demonstrated key advantages over bolt-action predecessors like the M24, particularly its semi-automatic operation that allowed for a higher rate of fire and faster follow-up shots during engagements.[8] Soldiers in Task Force Fury provided positive early evaluations, noting the M110's ease of maintenance and operational simplicity after brief training sessions.[8] Early operational experiences in Afghanistan's dusty conditions highlighted the M110's reliability, with the weapon performing consistently in harsh environments including sand and humidity, though some feedback prompted minor adjustments to components like the suppressor for optimized performance in prolonged field use.[11] In urban settings during the War in Afghanistan and Iraq War, the semi-automatic capability proved valuable for sniper teams providing suppressive fire, allowing them to engage multiple targets more effectively than with slower bolt-action systems.[10] By 2010, the Army had integrated the M110 into numerous sniper teams across these theaters, with production contracts supporting widespread fielding to meet ongoing combat demands.[12]Design and Specifications
Technical Specifications
The M110 Semi-Automatic Sniper System (SASS) is chambered in 7.62×51mm NATO and operates via a gas-operated, rotating bolt mechanism, functioning exclusively in semi-automatic mode without a full-automatic capability.[13][1] The system is designed for precision fire in diverse environments, with tolerances for operation in temperatures ranging from -50°F to 145°F (-46°C to 63°C) and resistance to dust and sand ingress through sealed components and dust covers.[14][15] Key technical parameters are summarized in the following table:| Parameter | Specification |
|---|---|
| Unloaded weight | 6.27 kg (13.8 lb) without suppressor or optic |
| Overall length | 1,029 mm (40.5 in) with buttstock collapsed and without suppressor; 1,181 mm (46.5 in) with buttstock collapsed and suppressor attached; buttstock adjustable for ~3-4 in length of pull variation |
| Barrel length | 508 mm (20 in) with 1:11 twist rate |
| Effective firing range | 800 m |
| Maximum range | 3,500 m |
| Muzzle velocity | 784 m/s (2,571 ft/s) with M118LR ammunition |
| Feed system | 10- or 20-round detachable SR-25 pattern magazine |
| Sights | Leupold Mark 4 3.5–10×40 mm day optic; compatible with AN/PVS-26 night sight |