The gun probably came from Cabela's...they're the best at messing up this terminology. The Navy revolvers were all .36 caliber, the Army ones were .44 caliber. To the best of my knowledge, until the advent of the metallic cartridge Colts (1873), none were chambered for .45. If you have something bigger than a .36, you should be able to tell easily by just a quick look at the chambers. Incidentally, the frame of the gun should have the caliber stamped on it somewhere; Colts have it above the rear part of the triggerguard on the left side. If yours says ".45" you're gonna have to mike the chambers, then pick a ball size a few thousandths over that size, so it'll seal up. If it says ".44", the balls on the store shelf marked ".44" will probably do fine. The front of the chamber should cut a ring of Pb from the ball as it's rammed home. There are many swaged balls for revolvers on the market...Cabela's has some; if you live near a Gander Mountain, they carry them (well, .45s, at least), and your local hole-in-the-wall gunshop might well have 'em. You can also order roundball moulds from Lyman in even thousandths, and cast your own. If using a cast ball, the spue mark goes up, next to the rammer; if you're using swaged balls, don't worry about it. If this isn't clear, post again.
