RIFLE: MASTERPIECE ARMS MODEL DEFENDER 5.7X28MM, SERIAL NUMBER FX03420, BLACK (MATTE), CASE NOT INCLUDED, SEMI - AUTOMATIC, 5.7X28MM, 16 Notes: The MPA Defender chambered in 5.7x28mm is a compact, modern firearm designed around the lightweight and fast-shooting 5.7 cartridge. It features a durable construction, compact profile, and practical controls, making it a distinctive addition for collectors and enthusiasts looking for a 5.7 platform. This MPA Defender is a unique option for anyone interested in the growing 5.7x28mm firearm market.