Troy, I have two Leupold VX III L/R's (30 mm tube, 50 mm objective, side focus, and good glass). One is on a .30 x .378 and the other is on a .338 x .378. No problems with either, but the Leupold warranty is good just in case. They can be bought for $700 - $800 or so. Be sure and use quality bases and rings. I like Warne, Weaver Grand slams, and Leupold dual turn-ins and QR's. They are all steel.
Just my opinion, Tom
Texas State Rifle Association Life Member
NRA Endowment Life Member
A big fast bullet will beat a little fast bullet every time