If you have concerns about overpenetration, stick with birdshot (I like #4, as I've found it won't penetrate much of anything, but carries quite a bit of energy at short range)....It'll still make a mess of the BG, acting almost like a slug at short range. Don't expect much spread, at the distances you're probably likely to encounter. As mentioned, try a few different loads, at known distances, to see what the actual spread is like. I use 00 buck, but I don't have to worry about overpenetration, as I have a free standing house (OLD w/ thick walls), and the nearest neighbor is 200 yards away.