I understood the " non-sporting use" 12 ga shotgun to be a destructive device. This included guns like the Stryker and Streetsweeper which are not semi-autos. It also included the USAS-12. I don't know how it would affect a 12 Ga gatling gun. You still might want to check on that one. I was also told by a gun dealer that the destructive device classification starts with a .68 caliber minimum. Does that mean any style cannon [ post 1899] can be built if it's under 68 caliber?
Never seen a .68 cal reference either. Seen reference to .50 cal. as the break between small arms and artillery in the Gun Control regulations, National Firearms Act and the International Traffic and in Arms regulations.
Muzzleloading cannon are antiques; you can build big and small as long as they replicate a pre 1899 design. Some restrictions apply if you build an antique that uses fixed ammunition.
It has always been the policy of this forum to leave the interpretation of the law up to ATF. If you need clarification contact ATF.
That being said this is what we accept on this forum.
1. Any firearm not designed or redesigned for using rim fire or conventional center fire ignition with fixed ammunition
and
2. Manufactured in or before 1898...or replica thereof, whether actually manufactured before or after the year 1898)
or
3. Any firearm using fixed ammunition manufactured in or before 1898, for which ammunition is no longer manufactured in the United States and is not readily available in the ordinary channels of commercial trade.
The Gatling gun has been always been allowed here as falling with in the spirit of the rules. However I also know that the rotary feed 12 gauge Shotguns have come under special restrictions. So the Standing board rule will be applied here.
No more discussion of 12 Gauge Gatling gun until a letter is produced defining it as not restricted.
We also do not want this board to become known for dissemination of bad or false Information