Modular Ambidextrous Rifle System - Heavy in .308 Win. The AR-10 big brother to the MARS-L, with full ambidextrous lower controls. Type: Rifle Action: Semi-Automatic Caliber: .308 Winchester Capacity: 20 Year introduced: 2014, USA Weight: 192 oz Overall length: 36" Status: Active Intended use: Military, Precision Shooting, Tactical