I'll be getting the 20 ga tracker barrel too, and I hope the barnes expander performs similar (obviously not the same) to the 12 ga load. Yes, when hit behind the shoulder they run a little, but with the 12 there is no doubt you hit them. Large pink spray pattern behind where they stood, and lots of sign to where they lay. I already bought some ammo for testing: rem ultra core lokt bonded, 3" fed barnes exp, and hornady SST.