if your goal is pest control, i say if you can see it you should be able to hit it. with a m16, i hit targets at ranges you almost couldnt believe; all with iron sights. once i was asked by someone with more rank, what the range of my weapon was. i responded that if i could see it, i could kill it. to which end he said "well, between you and that m16, the red army aint got a chance. push."
as time went on, he got chances to observe me shoot. after that, he liked me a lot.