Some time ago, I tried to get BSA to change their policy about allowing Boy Scouts to shoot flint guns in addition to percussion and in-line. It was a losing argument. The individual I spoke with at the NRA (name withheld deliberately) stated that flint gun accidents are about 6x more common than when shooting percussion or in-lines. Since I have no experience other than by observation with in-lines, I'll limit the discussion to flint and cap guns. In my personal experience I've had many more difficulties to get cap guns to shoot reliably, and those copper # 11's seem to blow apart all the time, presenting much more risk of fragmentation (yes, eye protection is mandatory). Dry-balls are much more difficult to clear, and pssst-bangs are much more common than with flint. Other than getting cut by a sharp flint, a shattering flint, burned by TH gas venting, or loading over a closed frizzen with a flint scraping it, (unintended discharge) I can't think of actually WHY they would provide more of a hazard than cap guns, but others here are likely far more knowledgeable about the subject than I. One clue he DID offer though, was that when he teaches Rifle and Shotgun instructors, most of them come to the class with experience in both arms. When he teaches new Instructors in ML'ers, most come to the class with pretty much zero experience in them. Anyone else care to comment?