I first saw a couple of Howdah Pistols at the Royal Armories in Leeds, UK. They were SxS break action pistols chambered in several of the big game cartridges in use at the time. I seem to remember them as rather plain working guns not engraved show pieces. I remember thinking the tiger would have to be climbing the elephant's trunk before I'd fire one of those pistols, the recoil must have been spectacular!
If anyone gets to Leeds go to the Royal Armouries Museum. It is well worth the side trip, plan to spend the day.