Anything in Hornady's V-Max line would be great. The NTX line also, I think. Anything loaded with Barnes "Varmint Grenade". Mostly, if it's 223 and it's ballistic/polymer tip then it's going to do a number on small critters. Most hollow points will also work just fine. The heavier bullets might be made specifically to NOT fragment, which is the opposite of what you want. If it's labeled "frangible" or "varmint", or any of the above, that's the ticket.