Ted, my only experience with the 220 RN's was from "back in the day," it was a popular bullet choice in these parts for bear hunting... I had many clients show up with these bullets loaded, and I was always pleased to see them... pretty much all in .30/06 or .300 WM. These were on black bears, not the heavy boned/muscled critters you are interested in, but a 400-500 pound bear quartering on is a pretty good test, the terminal results were predictable, good expansion, good penetration, good blood trails (when they actual moved after the shot)... rapidly dead animal. I would have no qualms using them on anything in NA when propelled by a .30/06.