I would love a original Howdah but the price! and the Howdah if made out of a Shotgun action would have to be registered as a pistol/handgun which can be done in Australia by notifying the police of the alteration but you have to be a Gundealer to do this. I would presume if you want to make a shotgun into a handgun in the USA you would have to get ATF permission first in writing.
RLI