We have several of both in the gun safe (or have had at one time or another). We load the .280s (including the AI) with 160 Partitions for elk. We load the 7mm RMs with both 160s and 175s. With these two chamberings, so far, we have had only two one-shot kills on bull elk--both with the .280s. That said, I can't really tell any difference in effectiveness in the field at the ranges at which we shoot elk. We don't shoot them at 300+ yards, primarily because we can almost always get closer. If we can't, we pass on the shot.
I played around with a 7mm STW when Layne Simpson first wrote about them, but found that, for me, the extra powder, noise and recoil didn't yield that much extra range. This was in a rifle with a 26 inch barrel that weighed well over ten pounds with a scope, sling and full magazine.
Admittedly, I am not a "long range hunter". I don't use a scope that goes higher than 9x and I don't trust turrets that can be turned by rubbing on my clothes or other gear. Confronted with a B&C bull at over 300 yards, I would probably twist the damned thing the wrong way anyway. I have seen both of those things happen with rifles carried by guest hunters that I have guided over the last ten years or so.
