Best ammunition for a tapered pistol?

If you use a 7.62x25 in it, you might shoot the taper clean out of it!

Now if you'll excuse me, I'm going to go back to shoving nickles up my nose.

Man I hate when that happens. I have fund this to be quite helpful in clearing the round. First lubricate the pipe, second load up the barrel with black powder, third heat the barrel with a torch (as the metal gets hot it will expand and the barrel will get bigger. When the barrel gets hot enough, the tooth picks will catch fire and ignite the powder, the powder will pop the round out the big end of the barrel.... Guaranteed to work!

You are almost right. The chamber tapers slightly to to accommodate the 9x19 cartridge. The case is .28 mm(.011) larger at the base than at the mouth.

You should use a Minie' type bullet for this gun! This way the forward end of the bullet will exit the bore,while the skirt of the bullet seals along the entire length of the bore. Confused yet? :)

Just bunch up Daniel's pantyhose and stuff 'em in there! Insert 9x19 round and, voila, you have a sabot round!