YouTube home gunsmith AK Custom crafted a bullpup magazine-fed semi-auto shotgun out of some common items, a $32 paintball lower and a little bit of his time.
The detachable 10-shot magazine borrows a spring from an M16 mag while the action, barrel, and bolt are made from a series of pipes and rods. The lower is a Raptor paintball gun which provides a simple but working trigger and sear. The contraption that he says has about 25 hours of his time invested in takes down with a flathead screwdriver and a 7/16 socket– no metric, here, folks! Paint the whole thing “Oregano green” camo and you are good to go.
Sure, it looks like a plumber’s dream, but so did the STEN SMG, M3 Grease Gun, and a host of others that seem crude but proved surprisingly effective.
Speaking of effective, check out the initial firing video below. Baby steps.