I attended a camp which used a venerable Winchester 10 GA. blank shotgun shell-firing cannon for the flag salutes. These can be fired safely with minimal training. I have heard of one accident only with one of these, when someone picked up one that was loaded and it accidentally fired with his hand or arm close to the muzzle blast. He was painfully injured but recovered. The reproduction Winchester cannons were about $400. last time I checked. This is a small investment compared to large medical bills and lawsuits that result from a cannon accident.
I do not recommend using a muzzle-loadiing cannon in any situation where the crew changes frequently, or is young, or is under pressure to fire rapidly, such as for the extra point when the gun is used to signal football scores at a game.
This is one of the reasons I recommended retirement of the Dahlgren boat howitzer (muzzle-loader) formerly used at US Naval Academy football games. I recommended the Academy use a breechloading salute gun instead. Eventually they did this. The cannon crew turned over people every year, and never did get adequate training. There was pressure to reload instantly to be ready for the extra point, and that worried me as much as anything they did.
