I have had a 375 Wby as well as two 375 Improved 40 degree rifles. I got increased velocities but also got recoil more like a 416 rather than the 375 H&H. I sold all three. I would rather have more bore and bullet weight if I am going to get that level of pounding. The RUM is even more “excitement”.
Incidentally if your M700 is accumulating brass shaving which clog the ejector then you may want to back your loads down and eliminate the brass extrusion.
