This is nothing more than a .45 Colt revolver with a long chamber which enables it to hold a 2 1/2" .410 shotshell. It is not a short barreled shotgun as it was never chambered for it. Having a rifled barrel is no indication of its being legal as a rifled slug barrel of less than 18" is still illegal. If one was to measure the bore diameter they would find it is of .452" or there abouts rather than .410" like in a .410 shotgun. If the words stating "Chambered for .410 Shotshell" were the only cartridge markings then you would likely need special dispensation from the BATFE but the addition of the .45 Colt to the mix negates that need. As for need, I don't see one but then again I bought a derringer in 45/70 so I may not be the right one to ask.