I can imagine that recoil would be quite severe. A .595 round ball weighs about 317 grains, just over half of that 600 grain bullet. This rifle also has a wide and flat buttplate, so it is not unpleasant to shoot with heavier loads.@roklok
I had the pleasure/ misfortune of firing a Hawken percussion cap 58 cal with a 600gn Minnie with the same charge.
I can say with great certainty with that curved steel but plate it sure got your attention when you touched old Betsy off.
Holy shit, lit me up like the 4th of July. I wasn't expecting that. I was told he was working up a hunting load for pigs. After seeing my reaction he backed it off to around 80 grains.
Bob