I was reading about 4 bores and their use in Africa. Only 4 roundballs
can be made from a lb. of lead for this rifle thus the projectile is
1/4 lb. The recoil can be astonishing. I did the math. Huge roundballs
make pretty good holes too. Here is a video of one being shot. For
every action there is an equal and opposite reaction. Yipes!

http://www.youtube.com/watch?v=ElmlIyOtf1Q