Slightly modified g&p m249. Upgrades done- -full seal vfc cylinder -6.03 tight bore g&p barrel -jg blue motor -shs 13:1 gears -ares polycarbonate piston with steel teeth -shs ball bearing piston head I also swapped the internal box mag connector to mini taymia. Gun shoots well, small areas of surface rust, shoots about 420fps. Wouldn't mind exchanging for a krytac kriss if someone is trying to offload one.