This is a custom built up discontinued Magpul M4. All of the internals have been switched for upgraded parts. Internals: Retro Arms Cnc red gearbox Shs 12:1 shortstroked 4 teeth Lonex ported cylinder Matrix silent cylinder head Kratos piston full metal rack Guarder Tappet plate Shs delayer chip Gate Titan advanced firmware Angel Custom tuneable trigger Shimmed and Lubed Asg 30k motor Prowin hopup with extended inner barrel Externals: G&p Moe receiver Moe hand guard Moe pistol grip Moe foregrip Pts enhanced polymer stock Valken T1 Silencer to cover inner barrel Please no trades and message with questions!