I have a few ideas that might help you. I was looking for the same thing only on Red fox and here is what I have tried and it works most of the time. 1. You could get the 30 grain Berger MEF drive them fast and these will blow up inside and should not exit. 2. You could shoot a Sierra 52 MatchKing at around 3500 to 3600 or the Sierra 55 Gamkeking I have had good luck with these out of my 220 Swift. 3. You could go with a Barnes 50 grain X bullet or a barnes solid. If you are calling them you might want to try shoot them through the chest because then your bullet has a couple of feet to go through and most of the time will not exit. Hope this helps.
Fast, Flat, and Accurate