Geissele GFR Stratomatch 6mm ARC rifles feature bolts made of a Carpenter 158+ alloy which is the result of the collaboration of Geissele and Carpenter and is superior to regular 158 steel. The barrel extensions of these rifles have feed ramps specifically designed for the 6mm ARC cartridge to ensure reliable feeding. The forward assist housing on the upper receiver is moved forward to provide more room for the operators hand when manipulating the right-side latch of the ambidextrous charging handle. The upper receiver also features a riveted stainless steel cam pin rail that prevents damage to the aluminum upper receiver from the steel cam pin rubbing against it when the action cycles.