The Marines have often had to follow the Army's lead on procurement. When the Army wants a rifle, the Marines have to get it as well. Part of this is due to logistics — it's easier to keep a single set of spare parts. When a unit needs more magazines, it's simpler to make sure they're sent the right part when choices are limited. Now, however, the script has been flipped.
The Army is now following the lead of the Marine Corps and buying a rifle that is based off a Marine project. The new Army weapon system, designated the M110A1, is a scaled-up version of the Marine's M38 that's able to fire the 7.62x51mm NATO round.
The baseline M110 is a Semi-Automatic Sniper System and is based on a rifle built by Knight Armaments System. The M110 features a 20-shot magazine and a 20-inch Chrome Plated 5R Cut barrel. The system has been used by the Army and Marines for over a decade and was considered one of the Army's best inventions of 2007.
The M110A1 is also designated the Compact Semi-Automatic Sniper System and is based on the Heckler and Koch G28/HK417 rifle. It is slated to replace modified M14 rifles currently in use by the Army. This is not the first time the Army has used a semi-automatic sniper system. The M21 sniper rifle was used by Army snipers in the Vietnam War. Adelbert Waldron was the top American sniper in that war with 109 confirmed kills. He was twice awarded the Distinguished Service Cross.
The M110A1 will be fielded among Army units later this year. Heckler and Koch, which makes this rifle, also sells a civilian version, the MR762A1.