Ohh, good luck with that

. I would advise a shot-gun Austin. Accurate, barely affected by wind, good ammo length.
A P90 on the other hand: Innacurate, not a long range of fire, affected more by wind, very little ammo space in the magazine, constant reloading.
Now, about that mail-box shooting, that isint very polite

. Why don't you call a friend and invite him to shoot with you? That is what my friend does with me

. Much more fun with a friend than a mail-box

.