Saeed has graciously posted my load data:

http://www.accuratereloading.com/375wby.html

Any constructive criticisms of the great old 375 Weatherby, a most versatile round?

Some excellent results with some great new bullets, and some old ones, as well as some factory ballistics in 375 H&H versus 375 Weatherby out of the same rifle.

Four different Bridger bullets including the Walterhog, and one Groove bullet, are notable.

Nice work Ron, those results are interesting. I use R19 in mine and didn't see where it was used in your tests, you might want to try it and see how it does vs the others.

Thanks for the data. Your results are quite close to what I got with my custom rifle.I settled on 87gr. of IMR 4350, Fed 215M primers, the Weatherby brass with the 300 SAF. In my 22" barrel this load gives 2675fps and MOA accuracy. This same load gives 2740fps in my friends 24" barrel. 30-06 trajectory with a 300 gr. bullet makes for a great round in my mind. The Weatherby is everything the grand old H&H is and a little more.

Thanks, John. I will have to add RL-19 to the next installment, along with VVN550, N-204, H4350, AA4350 ... 300 grain bullets only for Chapter 2.

Yea, who said you could use "my" buffalo picture?

Excellent, thoroughly excellent work. But then, I'd expect nothing less from you. I see your shooting remains superb.
Lots of punishment there. Good man.

Mark,
Now having fiddled with a 0.375" freebore length 375 Wby, I think you have chosen wisely. If I had to stick with one powder it would be IMR4350, and 87.0 grains seems to be the accuracy load for most 300 grainers, and a sub-maximum, safe load in the new chamber specs. But I could sure settle for Norma MRP, and need to try Norma 204, etc. (as above).

Good to see your results are close to mine. I didn't show any handloads with the Swift A-Frame 300 grainer, but I am in your ballpark with some other loads.

My old long throated 375 WBY preferred 88.0 grains of IMR-4350 in W-W Super brass, for about 2700 fps in a 24" barrel, with the 300 grain SAF, F215 primer.

What I showed is what I got, and I know it is a pretty small sample.

Brass make, throat length, bullet characteristics besides weight, and numerous other factors: Your mileage may vary.

Nick,
I guess Saeed volunteered your buffalo picture. Love that daga mud. Thanks!