Bull,
I've shot about 6-800 round through my 375 H%H and the Leopold 4X held up just fine.
Another bit of advice, most 375 loads don't require a mag primer. I load IMR 4064 which is close to RL-15 in burn rate and most groups are under an inch. I shot my cape BUFFALO WITH A Barnes 270GR TS. Plenty good for elk or the biggest bears
I've shot loads with RL-15, IMR 4064, IMR 4320, IMR 4350 and IMR 4895 and they all shot well, that the beauty of the 375 H&H