Like the magazine catch, the bolt release is a departure. It consists of a one-piece bar that extends across the bottom of the rifle just forward of the trigger guard behind the magazine well. Pressing down on either side releases the bolt. The optional ambidextrous safety transforms the Bushmaster .308 into the only fully ambidextrous AR-type rifle available. Bushmaster also eliminated the sometimes inconvenient charging handle latch, replacing it with a hidden spring-loaded detent in the center of the charging handle that engages a recess in the upper receiver.
The upper and lower receivers are made of forged 7075-T6 aluminum. About half of the .308’s components interchange with those of .223-Rem. caliber rifles, but none are stressed, so reliability is unaffected. Two versions of the Bushmaster .308 are available—an A2 type with fixed carry handle and sights and an A3 variant with a flat top upper receiver and a three-rail gas block. Barrels are rifled with four lands and grooves in a 1:10" right-hand twist.
The Bushmaster rifle came with an optional Ace Ltd. “ARFX” skeleton stock. This stock replaces the “A2” type fiberglass stock with one of hard anodized aluminum that is both lighter and stronger than the original. The stock has a closed-cell foam cover over the buffer tube. This provides a much improved cheek weld, and dampens vibration and noise. The stock comes with a 1/2" thick recoil pad that has a “tacky” feel that helps hold the stock in position.