It's both a rifle and a shotgun. 45 Colt and .410 shotgun.
I don't know if its still in production, or not, sorry. But I do know its either a rifle, OR a shotgun. If it has rifling, its a rifle. Period.
It can be (and is) a .45 Colt rifle that also shoots the .410 shotshell, but its still a rifle, technically. Same thing for the handguns that shoot both. They are .45 Colts, with rifled barrels, which are also cut to allow the use of .410 shells. If they weren't rifled, they would be shotguns (smoothbore) under the law, and couldn't be sold as regular handguns.
And, yes, the power of the .410 slug is impressive, for what it is. It's a 110gr slug (approximately) and the box of 3" Winchester I have says velocity is 1800fps. That's respectable, I think.