Those are the coolest Zip guns I have ever seen.
Just put a serial# and city/state of mfgr- if they are rifled.
So, that makes it legal?
You can manufacture your own gun for personal use. An unrifled zip gun is like a sawed off shotgun. Look at the semi-sten builds ATF may not be happy but they have not been shut down. It may depend on state or local law. I would trust some zip guns over a Raven or Lorcin any day. Any other opinions?
A zip gun will get you a better one when the chips are down, as has been stated so often
Another thought is the state like MD with a "Saturday Night Special" Ban all bets are off.
I'll have to see their definition of.