Started a horse once for Mounted shooting used 45 colt cases modified to take shotgun primers. Started off shooting maybe 10 to 15 yards from corral. Did not get much of a reaction so moved closer. Worked leading horse and someone else shooting the primers starting with them where horse could see once little or no reaction moved to where the horse could not see once no reaction achieved. Saddled up the horse and got on back to shooter where horse could see after a few little or no reaction passes, shooter where horse could not see etc. Then shot the primers from the saddle standing, walking, trotting, cantering each phase done until little or no reaction. Thne move up to bp charges standing etc. Horse was pretty good thru the whole thing. Never did the mounted shooting though they shoot for money so the suckers that are just starting pay the freight and the good ones collect the dough. Same reason I quit bulleye pistol competition.