IMHO you don't need ascope like that for a 375. You barely shoot over a 100 yards has been my experience in Africa. The 2.5X8 is IMHO again perfect.

A agree with Rich, but if you want to scope it, most hunting situations you’ll find yourself will be with lower magnification. I have a 30mm Leopold European 1.5-4 on a Number One, in 9.3x74. I think it’s ideal.

My #1 375 has a Leupold VarI X III 1.5X5

Also see Vortex made in China. Got to be made in USA

Found a Leupold 3.5-10x40 on Midway USA and think I will try that.

There's a difference between 'can' and 'should'. Fire forming brass is generally done with a reduced load, and using a soft lead bullet is recommended. Using factory ammo is OK in an emergency, But the Experts (George Nonte states it categorically) That using factory Magnum should be avoided because of the likelihood of gas blow-back. The greater difference in case and chamber, the greater the possibility. The same situation holds true if your intent isn't fire forming, but actually hunting, as there will be a significant drop in pressure, and ballistic accuracy. Not so much a problem poking holes in paper, but a charging Rhino may have a negative impact on your shorts.

I agree and as I hand load it usually isn't a problem. I have fired factory 7X57 ammo in my improved rifle without suffering any ill effects. I doubt Mills will become a hand loader. If he can return the gun based on it's non original cambering that would be his best option but I'll bet that ship has sailed.

Rambling opinion worth what it cost.

I use high power scopes, on the target range mid day good light & stationary target. Anything else low power is the best choice. Particularly large animals that are 100 yards away and can run.Fixed 2 1/2 is my favorite & suit the vintage rifles I prefer, about perfect pre 64 big bore M70. Modern Bolt hi tec synthetic stock gun variable 1.5 to 4 may be even better.

Go Leupold nothing else even close.

On the improved case. I had K Hornet in a T/C single shot that was successful. My 25 Kraig on a CPA Stevens 44 1/2 reproduction has been difficult extracting, probably re-chambering to 25/35. If I was hunting dangerous game in hot and posable dirty conditions would want a tapered case and controlled feed rifle.

William

40 years ago I had a 375 H&H with a Burris 4 power scope and quick detachable mounts. In practice the scope was used on game at some distance and it came off for close work. Burris was a great scope manufacturer half a century ago, but Leupold has the reputation today and great scope at a great price. Their VX3 1.5x5, is an ideal choice for the .375. It is the scope I use on my Ruger international 6.5x55 and 30-06 I had a Leupold 2 power on my 458. The best advice I can give is to contact your White Hunter and ask what he recommends. My advice is to take the rifle you have grown up with and use the bullets your WH has the most confidence in.

Mills

Another thing you should do, is check your hole spacing on the rear bridge it should be .435" ( that would be the case for the 375/300 H&H actions) likely they are 6-48 screws.

Sometimes we see these holes have been opened up for larger 8-40 screws on 375 and up.

This has been re chambered to 375 Magnum. Itg doesent say it's a H&H magnum. I wonder what it was originally chambered for.