Lewis Machine & Tool Company's LMT Gas Piston System is designed to upgrade the AR/M4/M16 series of carbines and rifles. It builds on LMT's CQB MRP platform and runs cooler and cleaner than standard direct-gas impingement systems. Its improved piston operating design allows the operator to use a greater variation of ammunition while maintaining the built-in accuracy of the LMT system. The Gas Piston System's bolt carrier is machined in one piece, an d the barell is free-floating and machine-gun rated.