Originally Posted by MontanaRifleman
Depending on barrel lengths, throats, powders etc., I would say close to 3000 fps would be expected on the high end for both the 180's in the 7RM and 210-215's in the 300 WM. 3000 fps is a typical max velocity for 160's out of 24" 7 RM and maybe another 50 fps for a 26". With the right combo of barrel and powder 3000 would be possible for 180's but 2800 fps would be more common.
I have shot 210's @ 2935 out of my 24" 300 WSM
When comparing apples to apples, a 300 WM is going to shoot a 210-215 bullet about the same velocity that a 7RM is going to shoot a 180.
EDIT: My 300 RUM shoots 210's @ 3130 over Retumbo
I have both a 7mm RM and a 300 WM pushing the very combos discussed here. The 300 WM is a factory chambered 26" 5r. I push the 215s with extreme consistency at 2840 fps.
You won't get 3000 with a 300 WM with 215s in a factory Sendero chamber with any sort of consistency. Truthfully, anything over 2900 fps is pushing the snot out of it. Especially if you are limited to a 26" tube. 2800-2850 is the comfort zone.
The 7mm RM will easily reach 2950 with a factory chambered
26" Sendero with a 180. 3000 might be a touch much, but 2950 is a very realistic expectation.