MASTERPIECE ARMS 5.7 - 5.7X28MM The MasterPiece Arms 5.7 chambered in 5.7x28mm is a semi-automatic firearm featuring a modern configuration and durable construction. It incorporates a metal receiver and polymer components, with design details varying by model. The MasterPiece Arms 5.7 utilizes a semi-automatic operating system and a detachable magazine. Its configuration features a centerfire cartridge platform and a compact, modern design. Chambered in 5.7x28mm, this MasterPiece Arms firearm combines metal construction and a detachable magazine system in a semi-automatic platform. Specifications - Manufacturer: MasterPiece Arms - Model: 5.7 - Caliber: 5.7x28mm - Action: Semi-Automatic - Operating System: Model-Dependent - Frame/Receiver: Metal - Furniture: Model-Dependent - Barrel: Model-Dependent - Magazine: Detachable - Sights: Model-Dependent - Finish: Model-Dependent The MasterPiece Arms 5.7 in 5.7x28mm features a semi-automatic operating system, metal receiver, and detachable magazine in a modern firearm platform.