Chuck, Consider sending your rifle to Jim Dubell at Clearwater reboring. He does wonderful rebores with reasonable wait times (3-4 weeks) and opening the 375 H&H chamber to 470 Capstick is way simple. This option would require no stock modifications, which could be non-trivial changing the recoil lug arrangement on the barrel. Also, with Jim, you could, within limits, specify not only twist, but also groove depth. Your rifle would get a bit lighter, which would provide more "satisfactory" recoil. Win, win

Otto