ok guys thanks for all your help
A) the site is four acres of woodland surrounded on three sides by fields owned by people who know what we're doing and have told us to go ahead.
B) I stopped by 42 division and told them exactly what we'd be doing, and we're all reasonably certain that playing airsoft at this site is legal.
C) As for insurance, these are all very good friends of mine who all graduated high school in the same year as me. I've spent four years with these guys and I'm quite certain they are all 18+. Nevertheless, I have a waiver signed by all of them saying they themselves are personally responsible for all injuries that they get playing airsoft in these woods. I hope I don't have to pull it out, but it's in a locked cabinet.
I believe in ordinance overkill
We're gonna need more BBS