MAC702 - The .58 Caliber "Minie Ball" projectile for your Model 1863 Springfield Rifled-Musket should be cast out of pure Lead. The grooves of bullet are filled with a Beeswax and Beef Tallow lubricant mixture.
Before 'live firing', a couple of percussion caps should be 'snapped' (fired) on your empty rifle. This is done with the barrel muzzle pointed at the ground. This burns up any oil in the nipple and barrel.
Grass blades on the ground will be moved and indicate the passage to the barrel is clear. Leave the Hammer 'down' on the nipple.
The Civil War muzzle-loading rifles were loaded with the butt-plate on the ground and Muzzle pointing nearly vertical. (Don't put your body parts over the muzzle)!
A paper cartridge containing approximately 70 grains of 2"F" Black Powder was torn open with the teeth and the charge was poured down the barrel, exposing as little of the hand as possible.
The Minie-Ball base was inserted into the bore and given a quick push with the fingertips.
The Minie-Ball was made slightly undersized, so that the ramrod could easily push it down the barrel and seat it onto the powder charge.
Once the bullet was in place, the rammer was sharply 'sprung' or bounced on the bullet. This action flared the base or 'skirt' of the Minie-Ball, locking the bullet into the rifling.
Firing the rifled musket creates high-pressure gases, that further expand the soft Lead Minie Ball, allowing the Conical bullet to be spiraled by the rifling as it travels through the bore.
If you Google Search "North-South Skirmish Association" and go to their web site, you should find lots of good information. Those guys have been doing this stuff, since the 1950s!
Some old Lyman Reloading Handbooks have chapters on shooting muzzle-loaders.