Describing the "kick" from a gun is always fun, since every one is different. My .30-06 has a really hard, sharp kick to it. Rocky's .58 caliber Civil War replica rifled musket had a much stronger recoil, but due to the slow-burning nature of black powder, it's less like someone punched you in the shoulder and more like they pushed real hard. It rocks you back on your feet, but doesn't hurt at all.
Another interesting thing about the Civil War rifled musket is the famous Minié ball. It was designed with a hollow back end, the idea being that the flange would expand and engage the rifling, ensuring a tight seal and eliminating the need for a patch between bullet and powder. It didn't work that way, at least not for us, so we got into the habit of patching it anyway.
When you fired the gun it wasn't obvious from the side, but the shooter could see that the trail of smoke from the gun to the target spirals a little, making a corkscrew effect all the way down the range. It's part of the fun of shooting the things.