The rifle that shares a name but serves two different masters

Wars & Conflicts · Published 17 October 2026 · Updated 25 October 2026 Swipe more like this →

In short: In the world of military procurement, the M110A1 is a study in bureaucratic complexity. While it shares a designation, it actually refers to two distinct weapons: a compact sniper system for stealth and a designated marksman rifle for squad support. One was meant to replace a legend; the other is currently doing the heavy lifting.

The M110A1 is not a single weapon but a dual designation for two different configurations of the Heckler & Koch HK417. The first, the M110A1 CSASS (Compact Semi-Automatic Sniper System), was designed to be a shorter, lighter version of the standard M110. It was intended to provide snipers with a low-profile weapon that wouldn't 'stick out' in the field. To achieve this, it features a collapsible stock and a removable flash suppressor, weighing approximately 9 pounds unloaded. However, despite being selected in 2016, the CSASS has seen stalled procurement due to funding issues, with no known fielding as of 2022.

The second configuration, the M110A1 SDMR (Squad Designated Marksman Rifle), is the variant actually seeing widespread use. It is designed to provide infantry squads with extended range capabilities, specifically to engage targets between 300 and 600 meters. Unlike the CSASS, which uses a high-magnification Schmidt & Bender 3–20×50 PM II Ultra Short scope, the SDMR is equipped with a SIG Sauer Tango6 1–6×24 low-power variable optic. It was officially designated to replace the Mk 14 EBR in the U.S. Army.

The naming overlap is a result of administrative convenience; by using the M110A1 designation for both, the military avoided the need to establish a new Program of Record. While the CSASS remains in a state of uncertainty—with the Marine Corps opting for a different Product Improvement Program instead—the SDMR has been fielded to nearly 6,000 units across the Army, National Guard, and Air Force. These rifles are chambered for the 7.62×51mm NATO round, allowing them to fire advanced armor-piercing ammunition that outperforms the standard 5.56mm rounds.

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