Quick view MasterPiece Arms Masterpiece Arms Defender, Mpa 57dmg 57x28 5in Tb Mb Sc 20rd $823.35 $649.85 Mpa's 57dmg uses a fully machined aluminum lower receiver and fully machined aluminum grips.The machining of the lower and grip reduces weight and increases the level of comfort and ergonomics from the previous design (mpa57sst).Each receiver is laser... Compare Add to Cart