A low mass carrier provides the most significant improvement to felt recoil after the addition of a compensator. JP's LMOS(TM) carriers remove much of the reciprocating mass out of the rifle's cycling. This translates into less felt recoil and less movement of the rifle. That means dramatically faster sight recovery and follow-up shots. This carrier group includes our proprietary bolt design, the JP Enhanced Bolt(TM). Superior in every way to standard bolts, it's manufactured from SAE 9310, providing drastically extended lifespan with design improvements that ensure superior function. Manufactured from SAE 9310, it has a drastically extended lifespan while de Mfg: J P Enterprises