I'm going to take a contrary position to most here. How does the last little bit of accuracy help to reliably kill elk? To me the bullet performance INSIDE elk matters more than 1/2" smaller group size. But then I don't choose to shoot at elk that are more than 300 or so yards away. I you do, and have the ability to shoot your rifle accurately enough in the field to take advantage of a tiny bit better grouping ability, it could change the equation. But I doubt it.
While 7mm NP 160's are very good elk bullets, 175's are just a little better at achieving penetration while breaking heavy bones. I have seen a few light and medium weight bullets stop when they hit the humerus or the head of the scapula on elk and moose. Their somewhat better ability to continue to penetrate on a straight course after hitting heavy bone makes me choose heavy for caliber bullets every time - unless considering the mono metal types.
