I am wondering if anyone is getting good accuracy and ignition with H&H level loads in the 375 RUM. I'm thinking of getting one and would like te reduced loads to go along with the regular power loads. I know in big cases with low charges and lots of space left over in the case can sometimes have ignition or accuracy problems, so I am hoping your guys experience with reduced loads in this caliber aren't causing problems.
Thanks

I have never used the 375 RUM but 378s are fine.

In the 378 85 grains of Varget or 4064 is a bit over 2600 with 270 grainers and a very mild load, about 10 grains under maximum and 3 shot 1 inch triangle shaped groups. Ditto for same load with 500 grain Hornady in 460 Wby and just on 2000 f/s

If you just reduce normal loads back then you will still get lots of recoil. The only gain is low pressure, sort of like 4350/4831 in 416 Rigby equalling 416 Rem with maximum loads.

If you use reduced loads like I mentioned the blast is also softer than a 375 H&H with its normal loads.

If I was to load for a 375 RUM and to get 375 H&H ballistics I would try Varget and 4064 and also 3031 burn rate.

For Varget and 4064 a load that is about 87% of a max 4350 charge will be max with Varget or 4064. So take that load and reduced about 10% and that will put you close.

If using reduced loads like this it is better if you can reload where you shoot. Reduced loads can shoot just as well and better than full loads but the powder charges that don't deliver the required accuracy can be quite poor. In other words the variation is much greater.

The type of poweder can make a big difference. For example, in the 378 using reduced loads of 85 grains of Varget, it will not shoot with another Australian powder that is about like 3031. Groups are 3 inches as opposed to 1 inch with Varget.

Lastly, the 375 RUM will be better than the 378 na dnot just because of the smaller case capacity bt rather the lack of a very long freebore. Very long freebore does not help when it comes to ignition.