KS Jeff, what broadhead are you shooting? That could have something to do with you getting pass throughs or not. You might be better off shooting a bit heavier arrow to. A heavy arrow has more punch than a light one. Given your only shooting 20 yards the speed you would be looseing wouldn't make that much difference.

I have never not had a pass through on a whitetail. I shot a Bear Jennings bow with round wheels for years. Then up graded to a Martin Phantom, 60 lb draw weight, with a single cam and with 80% let off.I shot gold tip arrows with 100 grain lighting broadheads from wal mart.The last doe I shot was at 15 yards and broad side. Hit just a bit forward and nailed the shoulder blades. Complete pass through even when I hit both shoulder blades. I don't think a older bow would have done that. There's alot of advantages with useing todays newer style bows over what your shooting. Something to think about.