--I ended by saying that a stray shot may injure someone, and could cost us all the use of our club.(Something similar to that).--
This may be the source of the anger. You probably didn't need to preach much about the possible outcome of a stray shot. IMHO, simply pointing out that it could happen would be sufficient. Everyone knows a stray shot is a bad thing, and I'm sure this fellow simply didn't realize the danger.