In April 2016 Heckler & Koch confirmed that a lighter version of the G28 had won the United States Army's Compact Semi-Automatic Sniper System contract to replace the M110 Semi-Automatic Sniper System. It is designated as the M110A1 and uses an aluminum upper receiver instead of steel to meet weight requirements, weighing unloaded and reaching some loaded and with accessories; the M110A1 features a Geissele M-LOK rail handguard, Schmidt & Bender 3–20×50 PM II Ultra Short telescopic sight, Geissele optic mount, OSS SRM6 suppressor, 6-9 Harris bipod and mount, and a collapsible stock with adjustable comb. In May 2018, the U.S. Marine Corps will begin receiving the CSASS, also to replace the M110.