I blew a drum out of a 1" .40 caliber barrel several years ago & it might have really injured someone had I not been on the range alone that day. I suspect a double charge with a drum that had not been well supported by the lock bolster for many years. The drum & nipple were found about 50yds away on the other end of the range by a club member sometime later. As it was, I only suffered powder burns/freckles on my left hand, but it could have been much worse. I hate to think about what might have happened if someone else had been shooting off-hand & had taken the drum & nipple to the head or face. I did not build the rifle I was shooting at the time, but if I can't use a patent breech on a percussion build, I make darned sure the drum rests on the lock bolster. And I'm not overly happy with that arrangement.
Roger B.