Carson McGarry posted his Spartan Airsoft SMG Kit which you can put together when you buy it as his Etsy store... "The Spartan SMG airsoft gun is one of my finest creations. It bridges the world of fantasy to real life. I've designed this airsoft gun to work with a Version III Ak gearbox. Each part is ready for 3D printing and can be purchased at Etsy. Also, shout out to Bensound for the royalty free music in this video."