It was originally a lm4 cqb first gen The upper reciever was replaced with a new one to fix the first gen splitting problem Parts list: DD mk18 rail 10.5in outer barrel Stock inner barrel but have a km head cqb barrel that will be included Maple leaf steel hop up chamber Maple leaf 70 degree bucking Magpul B.A.D. lever Ra Tech npas bcg Original bcg will be included with a danger werks flute valve 3 pts epm mags 1 original stag mag Magpul afg replica I'm sure im forgetting something but i will send more pictures and shooting video on request Price is at $300 but might be willing to work with you