My 375 doesn't seem to care for this powder with the 260 grain Partitions or the 270 or 300 grain Barnes solids or TSX bullets so I was looking at different bullets to try in it to burn up some powder and came across some strange information.

I realize that reloading manuals are only a guide, but really!

According to Hodgdon with H4350 the maximum charge for each of these bullets is:

250 g Speer SP - 83 grains
260 g Partition - 78 grains
270 g Win Failsafe- 83 grains
300 g Sierra SPBT - 78 grains

I realize that the bullet construction plays a part in pressure but this just seems not to make any sense to me.

There's 5 grains difference between the 260 Part and the 270 Win bullets and the 300 grain bullet has the same max as the 260 grain Partition.

Fjold -

It is an interesting observation but, gullible as I am, I can easily believe it.

Basically I read the info you posted like this:

250-270 gr. bullets, Max= 78 grains.

300gr.bullets, Max= 83 grains*

*Treat Nosler Partition 260's as if they were the equivalent to conventional 300 gr. bullets (in this case Sierra) because the Partitions have some of the following (choose one or more): thicker jackets, harder jackets, a solid section of bore diameter brass in the middle of their jackets, a less tapered ogive engaging the rifling, harder cores, and so on.



I don't know that the Nosler Partitions have any of those characteristics, but if they do, it can definitely affect the maximum loads they might be useable with to reach SAAMI max pressures.

As for my own .375 H&H Mauser, it seems to thrive on Hornady 270 gr. bullets and 75.0 grains of H-4350. Not a max load, so far as I can tell, but is certainly a good working load.

H4350 shoots really really well in my M70. I use 79gr with the 300gr Hornady RN and get MOA groups. The same load with the 270gr TXS also shoots MOA. If I try to load 79gr with the 300 gr Barns TXS it will buckle the case due to the much longer shank. I wonder if the FS has the same issue?

H-4350 is the only powder I have used in my M-70 .375 H&H. It was the first one I tried and it gave me good velocity and good groups with 270 Grand Slams and 300 Hornady FMJs.

My Brno 602 likes H4350 (ADI 2209 here).
81.2 gn with 300 gn Sierra gives instrumental velocity of 2666 fps virtually identical to an 80 gn load of IMR 4350 with the same projectile.

The H4350 load and the velocity equivalent load of IMR 4350 shoot into the same MOA group at 100m with the same projectiles and barely enlarge this group with other 300 gn projectiles such as the 300 gn Hornady SPBT and 300 gn Nosler partition.

Hi Frank,
I use IMR and XMR(Accurate)4350 as the best powders with 260 gr NP, 270 gr Hornady SP and all 300 grains. In my M 70 pre-64 the loads, Winchester cases, are:
260 NP-84 gr 4350-WLRM or F215-2770 fps
270 Horn-83 gr 4350-WLRM/F215-2700 fps
300 NP-80 gr 4350-WLRM/F215-2550 fps

All are safe and very accurate, aroun 1" / 1,5" at 100 meters.

PH

I use IMR4350 with the 260 grain Partition and my gun loves it. I'm using H4350 in my 6.5x284 and was hoping that my 375 would like it also so I could have less powders in my cabinet but no luck.