I fired my original 1863 Springfield today for the first time. That thing would make a Christian out of anybody within 500 yd! I used a medium load - a .58 cal Minie ball and 50 grains of 2f Swiss powder.
For my first shot, I didn't hold the rifle butt against my shoulder quite hard enough and I also made the mistake of resting my cheek against the stock. Even with hearing protection (muffs), I had a slight headache after a dozen rounds, probably due the concussion blast as much as the recoil. It ain't no lady's rifle.
Anybody studying the American Civil War would be well advised to shoot that gun, or any M1861 variant - it will change your perspective. I have a couple of .50 cal. roundball muzzleloading rifles, and there is no comparison. Likewise, a .30-'06 is comparatively tame.
Here is an excerpt from the U.S. Ordinance Board's test report on the 1861 .58 cal. Springfield:
"The standard load, a 500 grain .58 caliber Minie' ball backed by 60 grains of FFg, was found to penetrate eleven 1" pine boards at 100 yards and six 1" pine boards at 500 yards." Here's the link: http://morro-bay.com/morsels/manny-s...ield-rifle.pdf