Heckler & Koch M110A1
CSASS | SDMR
Overview
H&K M110A1 SDMR
US Army soldier with M110A1 SDMR in 2021. Note the regular stock and 1-6x LPVO sight.
Source: US Army -
© Public domain
Over 7.000 SDMR ordered since 2020
SDMR (Squad Designated Marksman Rifle)
Description
Introduction
The M110A1 is a modern era marksman rifle of German origin. The M110A1 was developed for the US military Compact Semi Automatic Sniper System (CSASS) requirement. The HK 417 serves as the base platform. In a different configuration the M110A1 was later selected under the Squad Designated Marksman Rifle (SDMR) requirement.
Design
The M110A1 CSASS is based on the HK 417 marksman rifle. As such it is a gas operated firearm using a short stroke gas piston. Strict weight requirements resulted in different design choices from other HK 417-based marksman rifles. Unlike the German military G28 variant CSASS uses an aluminum receiver instead of steel. The CSASS uses a Geissele MLOK handguard, two-stage trigger and optics mount. A Harris bipod and OSS SRM6 suppressor are issued as default with the rifle. The later SDMR configuration is very similar to the CSASS, differing in standard type of optic and type of buttstock.
Firepower
The M110A1 CSASS is a semi-automatic marksman rifle chambered in 7.62x51mm NATO. It is a semi-automatic rifle using a 20 round detachable box magazine. It is able to fire the Cold War era ammunition types and the newer improved M80A1 ball round, as well as the M1158 Advanced Armor Piercing Round. Effective range and accuracy are likely in the same realm as other HK 417 variants with 16-inch barrel. This makes the CSASS an effective marksman rifle in the 800 m realm. The 1 to 6x magnification of the optic used on the SDMR it is configured for short to medium distances, ranging from point blank to about 600 m.
Users
The M110A1 in CSASS configuration was acquired in small numbers and field tested from 2017 onward. Funding for the larger scale acquisition seems to have been postponed, or even cancelled. Fielding of the M110A1 in SDMR configuration started in 2020 with the US Army, including the National Guard. From 2022 onward it was also introduced in the US Air Force.
Variants
M110A1 CSASS
In the CSASS configuration the M110A1 is fitted with Schmidt & Bender PM II 3-20x50 Ultra Short scope and a retractable stock with adjustable cheek piece.
M110A1 SDMR
In the CSASS configuration the M110A1 is fitted with SIG Sauer TANGO6 1–6x24 low-power variable optic and a more conventional wide model stock without cheekpiece.
Details
Related articles
Heckler & Koch G28
The M110A1 was derived from the H&K G28. The most visible difference is the use of a lightweight MLOK handguard.