When I started rifle hunting the 7mm was the first cartridge I used loaded with 160 gr bullets. It seemed to anchor animals well. When I wore that rifle out I then tried the 300 WM and WSM, both also worked well at anchoring animals. As I get a little older it seems I am becoming more recoil sensitive so I switched back to the 7mm. The 7mm seems to be the threshold of comfortable recoil in the weight rifles I like to carry. I hunt mostly elk but if a chance at deer came along I wouldn't hesitate to use the same 160 gr bullets and not expect much meat damage.
7mms are great all around long range killers, my only advice is to avoid belted cases if you can..
If you're building a rifle I'd look into a 7 SAUM for sure, ADG just released Saum brass so it's a no brainer.
If you're going factory get the 280ai, as others have pointed out you'll be very close to a 7RM with less recoil and no retarded belt.
Also make sure you get an 8 twist for the 180 Eldm, great bullets!
I think your good with either a 300 or a 7 RM. I am wondering what platform your 300 WM is in? If you are shooting for example a stock tikka then no doubt I would not reach for that over the 6.5 either. Slapping a break on it may just make it tolerable for you to grab. The 7 RM will all things equal be less brutal to shoot than a 300 WM, but the same issues around pleasantness to shoot will still occur. If your thinking about a do it all caliber both will be just fine. You need the right combination of rifle weight and recoil reduction that will fit your goals for shooting.
So far the best performance I have seen has come from the 180 Scenar. My 8.5 twist is good but if rebarreling I’ll drop to a 8 twist. I have seen the 180 eld-m not penetrate well at impact speeds over 2700 FPS. Love my 7mm but not sure it outperforms a 140 6.5 vld by much.
Thanks for all the input guys, really appreciated! You've given me a ton to think about so I guess I'll just wait for the Creedmoor to sell and stare at ballistics charts all day. Except now I have this 280AI to skull**** also. Again, I really appreciate the advice!