This was a Classic Army G3sg1 that I converted to a g3ka4. I shortened the barrel and cocking tube to appropriate size and added a real steel steel handguard. The lower grip is a G&G navy grip. I also installed a 3d printed steel locking mechanism for the collapseable stock since the original ones are prone to breaking. It shoots around 400 fps with .25. Comes with 3 hicaps and 2 standard mags. Internally it has the following: Bloomies zci rhop barrel with modify flat hop bucking. RA gearbox with modify ceramic bearings. Shs nozzle, cylinder head, piston head, and full metal rack piston. Prometheus flat tappet plate. Shs 18:1 gears Zci torque motor. Btc Spectre mosfet with Dean's plug. Price includes shipping. Please add pp fees **My field only allows semi only and I'm not certain if the mags feed properly on full auto**