I think the OP should let things settle for now. He has raised an objection to the individual and had he replied "So what" it might be different. He was'nt happy to be called out and perhaps this will make him think a bit. It might also be an idea to call on him in a couple of days time when you have cooled a little and first off apologise for getting heated but follow this up with a more tempered discussion of the rghts and wrongs - point out that you are a shooter and while you are sympathetic you don't want to do anything to increase focus on the ownership of airguns.


BTW what do the other neighbours think about this behaviour? Have you discussed it with them?