Supposedly (haven’t verified myself) the 300 win mag long enough you can get within 100 FPS of it. I’m going to copy and paste a quote from another website of a guys 300 wm with 215’s:This is absolutely not correct, anytime you can run a 215 Berger at 3050- 3100 in a 300WM let me know with the same length barrel
In my rifle I running 83 grains of H1000 in Norma brass, and getting 3030 fps out of a 25" barrel. My OAL to the ogive is 3.010".
In the two CA Ridgelines that I've been loading for, we are running 75.5 grains of H1000 in Norma brass and getting just under 2800 fps with 26" barrels. The OAL to the ogive is 2.900". We are not seeing any pressure at all with this load, and I'm sure I can push it a little more.”
If you’re already having a barrel reamed like OP is, I don’t see why you wouldn’t do a long throat if you have the option. I’m not saying the win mag is as powerful, it’s not. I’m just saying for the downsides of it, it’s not worth the bump in performance. And if I wanted to really push the heavies fast, I’d jump up to the RUM.