Not quite a .275 Rigby, but my crew has had excellent results with 160gr NPs in the .270, at about the alleged top velocity folks claim with their 7mms, 2700fps. Just Eastern Whitetails, but for whatever reason, they seem to drop right there or just a few feet away. One of those combos that just works, so even though lighter monos probably penetrate just as well, I suspect the NPs fragment enough to get it done quickly.
It occurs to me that a 7-08 Fieldcraft with 160s would be pretty much the same thing, but in a very handy package; dangerous thinking for an old fat man who already has too many rifles.
