CARTRIDGE arms during the American Civil War were pretty much Burnsides, externally primed Sharps, 44 Henrys and .52 Spencers. Throw in a few Black powder 22s, 32s, 38s, maybe a very scarce 41/44/45.
In general, the cartridge arms had smaller powder loads than a .69 caliber rifle, and would have significantly less energy than a pre-war arm. Of course, the definitive answer would be reached by taking a steel target, and shooting it. Examine after shooting.
What the heck are you guys planning to shoot?