No other MSR packs more firepower and functionality per ounce. With its rifle length AAC Square-Drop handguard the all-new Minimalist SD allows for fast solid attachment of accessories at seven different angles. The Mission First Tactical Minimalist Stock is as light and adaptable as it is comfortable. And the 16” 4150 lightweight contour barrel is FNC treated to stand up to hard use in any scenario. - Caliber: 223/5.56 - Magazine Capacity: 30 - Barrel length: 16” - Rifling Twist Rate: 1:8 - Overall length: 35” - Upper Receiver: A3 Flattop - Barrel Material: 4150 Chrome Moly - Barrel Finish: Melonite (FNC) - Barrel Contour: Lightweight - Avg Wt. 6.0 lbs - AAC 51T Flash hider - New AAC Square-Drop handguard with full-length rail