Tomorrow I pick up my .375 HH AI. I am leaving for Africa at the end of Feb. to hunt ele. If you have any loads with .300 gr bullets, let me know. Hopefully I will be using my .470 NE, but will be hunting the Nabib desert and it can be hard to find the flora necessary to get close. The PH said bring a scoped rifle just in case. Any loading assistance will be appreciated.

Just a thought, but I'm sure you can start with 375 JRS loads,

It's a similar design isn't it ! Using the improved 8mm Rem Mag case


regards
S&F

venado,

If you don't have time to develop loads for your rifle, just take .375H&H loads. They'll work just fine.

George

Just use 375 Wby data, as there is almost no difference. There is some good data here at AR.

George, I built the Ackley Imp. just for that reason. When travelling on a hunting trip it makes no sense to me to have a cartridge that is unavailable if your ammo is lost. My friend had that happen in Mongolia and had a 270 Wby w/ nothing to shoot. Perhaps I can use S&F's suggestion on working up a load. Thanks for the help!

Page 488 of the Ackley book #1 shows 85gr of 4350 gives 2,650 fps with a 300gr bullet for an AI and 2,655 out the 375 Wby. You can't get much closer, and P.O. says that the data is interchangable for the two.

Expect slightly lower velocities from 375 HH ammo when fired in an improved chamber. I would guess approx. 100fps.

Go to Loaddata.com they are a great source. Here's the load I settled on for my Pre-64 375 Improved. 75.2 grns IMR-4350 , 300grn Woodleighs soft or solids, Fed 215 large mag primer, velocity ran 2430 to 2440. cases were pre fire formed, C.O.L. was 3.563 Very accurate one inch group and the solids grouped aprox .5 inch higher than softs

Gentlemen,

Thanks to all for the assistance. I should be on the trail to my final load.

quote:

Originally posted by venado:
Gentlemen,

Thanks to all for the assistance. I should be on the trail to my final load.

I had the exact same question a while back!!
https://forums.accuratereloading.com/eve/forums/a/tpc/f/...?r=29610645#29610645

quote:

Originally posted by venado:
Gentlemen,

Thanks to all for the assistance. I should be on the trail to my final load.

Try 83 grains of Reloader-19 with Federal 215's. This will be a very mild load. Load 3 of each, increasing one grain per successive 3 cases.
Keep watching for pressure signs. You should be able to get 91 grains stuffed in there.
BUT please start low!!! Mine was a rechambered Brno ZKK 602. 91 was MAX in it.