Bumping back the shoulder - 375HH?

[50Gunner]

A lot depends on the chamber in your rifle, with my 375 and 300 H&H's i set size die so i can just feel a slight crush fit on closing the bolt, think of it as a cone in a cone in a cone, that snug fit absolutely turns the bullet loose in direct centerline of your bore, particularly in push feed actions with the little ejector plunger pushing on one side of the case head in FL sized cases, may not mean much, but i'm after all the accuracy i can get.

All the accuracy we can derive will certainly help from field shooting positions.

 

[450 Fuller]

These are excellent points in reloading the 375 Holland cartridge. I tend to stalk hunt closely
for game animals, with a controlled action pre-64 Model 70. Bullet selection may also be critical as to accuracy and reliability. Good results have been obtained with Swift, Woodleigh, Hawk, North Fork and
AK Bullet Works-Kodiak bullets. Some of these makers are no longer with us.
I also tend to stick closely to factory velocity specs with either 300 or 270 gr bullets, as reliability and repeat shots may be necessary. Some Hodgdon powders are stable with temperature variance: important in Alaska or Africa. Reliability cannot be over emphasized.

 

[Lone Star Bluegrass]

That sounds similar to the practice adopted by PO Ackley decades ago. I also only have one 375,
and neck size practice or load developing rounds. But I managed to obtain a separate neck sizing die.
The original British loading of the 375 H&H
used long strings of cordite powder. This also contributed to the belt and sloping case design.
Interesting that the 416 Rigby case did not incorporate that principle and appears modern, though developed close to the same time as the 1912 Holland cartridge. Both used cordite. The 416 remained a proprietary cartridge with Rigby-while H&H released the 375 to the rifle trade, Kynoch may have
helped Holland with case design. The 300 H&H came later, a necked down 375 case that still used cordite powder.

416 Rigby has a 45 degree shoulder. Not the right angle of a rim but almost as easy to duplicate for headspace purposes.

 

[Nevada Mike]

In my limited experience, chambers on my belted cartridges are a little longer than those on rimless, non-belted cartridges - compared to SAAMI specs. But head spacing does matter for repeatable reloads. I use Redding and Lee dies for the .375 H&H and do not bump back the shoulder.

I like Ray B's method and will try that to get proper head spacing in the .375 H&H.

 

[450 Fuller]

Roy Weatherby borrowed the 416 Rigby case and added a belt during the 1940s and 50s for his
famous 378 and 460 Weatherby cartridges. The 416 Weatherby was a later addition.
All of these cartridges were warmly loaded. The later actions made by Weatherby were a bit
stronger than his original Mauser-based actions. Probably a smart move for pressures developed.