Reloading the .375 H&H Magnum; first attempt with salvaged components.

[Trey Veston]

I inherited a beautiful Ruger #1 in .375 H&H Mag built by Roger Biesen and used in Africa by my father. While going over the inventory of rifles, my half-brother saw it and fell in love with it. He's a Detective and been having a rough time lately with back surgery and some tough cases. I decided to give it to him for Christmas, with the stipulation that it stay in the family. He's raising his two sons as hunters, while mine became leftists.

So, while nearly all of my father's reloading components and equipment was destroyed in the fire, I have managed to salvage quite a bit. However, I only recovered 10 loaded rounds of .375 H&H, and 20 cases. I went to buy ammo and found it is just not available in this area, which I found odd since we do have elk, large bear, and moose around here. Even Sportsman's Warehouse doesn't stock it and wouldn't order any in for me. The stuff I found online was around $5 per round! My stepdad found some down in Yuma, AZ on the shelf and picked up a box of Federals for $100.

But, I want to gift the rifle with at least a box of ammo. So I went out to my storage unit where all of the smoke and water damaged components are and dug through it for about an hour. I found two boxes of 300 grain bullets and an RCBS die set that wasn't too rusty. Success!

Looks like my Hornady handbook shows quite a good powder selection but only data for two 300gr bullets, both of which are Hornady. I only found Nosler and Sierra. I will be loading lighter range loads so my brother can shoot it without aggravating his back, so I should be fine using the data for the Hornady bullets, right?



I also found around 50 empty cases of .375 Ackley Improved, which I have never seen data for or seen a rifle chambered in it.

 

[bigpower491]

I know I'm not the first person in the world to use data for the same weight bullets by different manufacturers. Whenever I've found that to be the only option, I start right at the minimum charge and work up slowly. I personally would work it til I found that first good load and check it again for consistency. If all good there, there's your box of ammo. I wouldn't be going for max velocity without the proper data for a given brand of bullet, but you can compare your book data to say something like Hodgdons and see how the max charges compare for a given weight between the 2 sources. Chances are you may be using one of the powders under the Hodgdon family of brands so you should be able to get an idea of how far you may want to push it. The key to it is careful work up

 

[Palladan44]

Light 375 H&H loads so as to not further aggrivate back injury? Hmmmmmm......Maybe Elk hunt with a .270
Sorry, I had to give you at least a little lip about it...

That's a great score there, both on the rifle and the prospect of loading for it.
I'd go with powders faster on the charts that are suitable for the caliber, such as CFE223 . Those will likely give the best results with lower end pressured loads.
I saw some Retumbo on the shelf at Cabelas the other day, but something like that would be best run full tilt....probably not the best.
Good luck, tell us how it goes.

 

[Nullcone]

You also have a set of 40 degree 375 Improved dies... are you sure you don't have a rifle chambered in 375 AI?

 

[Trey Veston]

You also have a set of 40 degree 375 Improved dies... are you sure you don't have a rifle chambered in 375 AI?

Good eye! I didn't notice that.

When doing a search for info on the 375 AI, I came across the actual rifle, that was for sale on Guns International. The ad states that is chambered in 375 AI, even though the barrel is marked as 375 H&H. I thought my dad had this rifle for years. Obviously he didn't.

 

[LoonWulf]

I have some 235 speers i can share with you for reduced loads. Those over 4895 at 2600fps or so are quite pleasant in my 8.25lb .375 Ruger. Even the speer 270s at 2600 are very pleasant.

 

[Robert]

I load 270gr Barnes TSX using IMR 4895 and it yields an easy to shoot, middle of the road, accurate load. It's somewhere in the 2700 fps neighborhood.

 

[AJC1]

375 Holland & Holland (H&H) Magnum Load Data

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[sugarmaker]

300 gr sierras shoot well with 4350 in my gun. Varget and 4895 also shoot well as a somewhat reduced load but I find the groups don’t tighten up until the pressure is high enough to clean up the burn, somewhere midway between suggested starting and book max. Tolerable but a 375 is not really a mild gun as you know. Magnum primers are a must, esp. if cold weather shooting is on the roster. I’ve had 4895 hang and misfire at about 10 degrees with a standard LR primer. As someone mentioned, the 235 Speers are a good bullet, somewhat economical, and begin shooting well at around 2850 fps over the chrono in my gun using 4895 or 4064.