compressed .375 H&H loads

[matt85]

I come from a background of loading BP cartridges so compressing a load is nothing new to me. however from my understanding heavily compressing smokeless can lead to major pressure spikes. on that note, my Hornady manual says the max load for a 300gr bullet using W760 is 78 grains but with the 300gr BTSP that is some pretty serious compression. so far ive tried up to 75 grains of W760 which is a compressed load and i didn't notice and pressure signs. im unsure if i should try going for max due to compression but id like to get these puppies to 2500 fps for long range work and according to the manual this should be possible with 78 grains.

what are you thoughts on this? also general thoughts on compressed loads with African magnums?

thanks
-matt

 

[sestoppelman]

No worries with the compressed loads. I would think that 78grs of 760 should give you your 2500fps. I use about 81grs of IMR4831 which is somewhat slower powder and get over 2500. Being that 760 settles so well, I am surprised its so compressed with that amount. I never used 760 until recently and have found it to be a very useful powder, especially for near max loads without compression. My load was heavily compressed as extruded powders fill the case much more.

Just for kicks I just tried a load like yours. Using a fired empty primed Rem .375 case I dumped 78gr of 760 in and tapped it down some. Placed your bullet on top and it slid down to almost the cannelure before touching the powder and could be easily compressed with finger pressure. That is nothing to be concerned about. If you don't have a chronograph, now is the time.

 

[matt85]

I went ahead and loaded up some cartridges at 74, 75, 76, 77, and 78 grains (6 of each) using neck sized brass. at 75 you hear a slight crunch and at 78 you know you crushing some powder but I think it will be fine. the compression wasn't as much as I though it would be probably because the brass is neck sized instead of full length sized.

I can tell this powder wont work with my Barnes 300gr bullets, those suckers are way too long.

-matt

 

[jlb1036]

WITH IMR 4350 AND 80.0 GRS WITH 300 GRS IS AN EXCELLENT COMPRESSED SAFE LOAD
AND TRLY CHRONOGRAPHED AT 2610FPS OUT OF 24'' BBL
BOTH CZ /WINCHESTER AND BLASER

 

[geoff rath]

If we stick to recommended load data from various component suppliers, WOKING UP, AND LOOKING FOR AN ACCURACY LOAD FIRST, we'll have no issues. My playing with the 375H&H was a Sako, which someone silly sold. It went to Africa, without me. The loads I worked up using 300grain bullets worked; I saw the "after" photos...

 

[jlb1036]

that load that i mentioned is very accurate i can get 1/2'' grp @100yrds specially with the sierra 300 grs btsp.

 

[Nevada Mike]

If you go to a flat based bullet (like a Swift A Frame or Nosler PT) you should get less compression or slightly more powder - depending on the powder used. Swirl charging will help settle the stick powders in the case, maximizing available case volume. Highly compressed loads should be crimped - I prefer the Lee Factory Crimp die.

You can buy properly head stamped 280AI brass from Nosler or Peterson. Worth the little extra money, IMO. I used a 7mm RM (with similar velocities to the 280AI) and 160 Swift A Frames for PG and had very good results on animals up to zebra and roan in size.