1- I use .27 cal Hilti shells with a variety of projectiles. Round .25 bbs (any sporting goods store), .25 bullets cut in half etc. even .25 auto bullets work. I drop the bullet in and shoved the shell in behind it. Some guys have suggested putting some powder in with it, but its pretty obvious they've never tried it, once you shoot it without!
Ive also glued, epoxy'd, siliconed, JB welded the bullets to the shells. It all works. Silicone stuck on bullets are great as they wont break off while handling and carrying.
You can get the Hilti's at Home Depot, Ronas, etc. They come in yellow, brown, red and maybe the odd other colour. Yellows are pretty good, reds are pretty hot. Use the .27 cal ones. They fit better than .25's and will work with the extractor (25 wont)
2- I've also since been playing with .25 auto's in it. I reload with black powder. Works very well in some guns. It depends on the gun, though. The firing pin isnt in the same place on all. It works on mine most of the time. I've been considering moving the pin down a bit (only takes drilling another hole)
The extractor also works most of the time. Theres just enough rim on a .25 auto for it to catch, it depends on how worn everything is and how it was made.
These guns seem to have been manufactured with fairly wide tolerances.
To sum it all up, my favorite ways to shoot are: *Yellow Hilti w/ loose round ball for plinking.
*Red Hilti w/ silicone stuck-on .25 auto bullet for accuracy.
*Black powder reloaded .25 auto cf.
Once I drill a new hole for firing pin and build up the extractor a bit. I will probably use this exclusively just out of convenience.