375-338 load help

Decker9

Decker9

CGN Regular
Rating - 100%
42   0   0
Long story short, I have a custom 375-338wm built by my grandad that I recently acquired. It came with a box of reloads which I shot most of and all shot well. In the box is wrote 70gr of IMR 4350 and 235gr Speer. I have a box of Speer bullets that came with the rifle, so bought a new can of IMR 4350 and Sellier & Bellot magnum primers (his notes say Winchester magnum primers) and went to the range.

I loaded a few working up from 68.5 to the 70gr load, the lesser few loads produced a lot of blackening on the cases, the 70gr loads, most did, but some cases looked ok. I’ll share a photo of cases from the full 70gr loads.





Would this maybe be an under pressure issue? There is still room for a few grains of powder in the case and I don’t see and pressure sign, also, the velocity seems slow for the combo and it’s 22” barrel?

Another question, would H4895 be a candidate for a reduced recoil load for this cartridge? I don’t hunt over 200 yards, so really don’t need the horsepower, but I do want to use my grandads rifle.

Any input on how to figure out a reduced load would be appreciated. I load my h&h 1 grain under minimum book load with H4895 and really helps manage my boney shoulders, but I don’t see much online for the 375-338, other then a couple charge weights that exceed h&h’s book max lol.

Thanks in advance!!
 
I think you'll want to use a faster burn rate powder than 4350. I'd look at 4895, 4064, RL15, Varget, Win 748, Ramshot TAC, StaBALL Match, 3031, CFE223. 4350 might have an application in this cartridge if you're loading 300+ grain bullets
 
todbartell said:
I think you'll want to use a faster burn rate powder than 4350. I'd look at 4895, 4064, RL15, Varget, Win 748, Ramshot TAC, StaBALL Match, 3031, CFE223. 4350 might have an application in this cartridge if you're loading 300+ grain bullets
Click to expand...

If I could get away with H4895 that would be great as I have a bunch and use it with other rifles. Any thoughts on a place to start using H4895?

Thanks for the input!!
 
I'd back off 375 Ruger or H&H minimum loads by 10% and work up. No ignition issues at lower charge weights with H4895 so you won't run into problems being too conservative
 
I loaded up a handful working up to 64 grains of H4895 and 260gr partitions, and went up to 73gr of H4350 in .5’s and 260 partitions.

I gotta start my night shifts tonight, but will have a report next week on what I find, hopefully enough pressure to clean up the soot issue, and still enough for moose and bear inside a couple hundred yards.
 
Look for 375 Taylor loads basically what you have.i tried looking in Ammo Guide but I’m in a hotel that blocked it.
 
dan belisle said:
There's some data on that in Ackley's books. I'll see if I can dig it up. - dan
Click to expand...

I have a custom 375 Chatfield Taylor. Checked my:redface: 'tattered' copies of Ackleys books, volume I and Volume II. In volume I, pg. 212, there's a listing for info and load data on the 375/338 Chatfield Taylor. Then, in volume II, pg. 483, there's info and load listing for the 375 Durham Magnum. Both are stated as basically being formed by necking up the 338 Winchester Magnum case, to 375. Powder used in the 375/338 Chatfield Taylor is 4064 whereas those loads listed for the 375 Durham Magnum are listed using H380.
 
dan belisle said:
Looks like I can't upload any more pics. Send me your email in a pm and I'll send it to you. - dan
Click to expand...

Thanks Dan!! A fellow forwarded me a photo of the page from the Ackley book :). It lists 75gr of IMR 4350 with the 235gr Speer. I decided to switch things out to a 260gr partition instead, I worked up from 70gr to 73gr with the IMR 4350. Hoping I can get up this weekend to test them out. I’m looking forward to pa king this one for bear this spring.
 
Decker9 said:
Thanks Dan!! A fellow forwarded me a photo of the page from the Ackley book :). It lists 75gr of IMR 4350 with the 235gr Speer. I decided to switch things out to a 260gr partition instead, I worked up from 70gr to 73gr with the IMR 4350. Hoping I can get up this weekend to test them out. I’m looking forward to pa king this one for bear this spring.
Click to expand...

Good. Let us know how it works out. - dan
 
:dGood day today. I have a more than adequate supply of brass for my 375CT, formed/necked up 338WM brass. However, recently I was contacted by a site member and offered a 'treasure'. Two bags of 20 brass, head stamp 375 Taylor, made by a U.S. outfit by the name of Quality Cartridge.:d Made my day as it fits in well with my preference for the correct head stamp on brass & cartridges for firearms I have. On a related note, I only have one caliber/cartridge that does not have the correct head stamp. A 219 Donaldson Wasp and that I have in an old custom Winchester Highwall.
:cheers:
-JP
 
Johnn Peterson said:
:dGood day today. I have a more than adequate supply of brass for my 375CT, formed/necked up 338WM brass. However, recently I was contacted by a site member and offered a 'treasure'. Two bags of 20 brass, head stamp 375 Taylor, made by a U.S. outfit by the name of Quality Cartridge.:d Made my day as it fits in well with my preference for the correct head stamp on brass & cartridges for firearms I have. On a related note, I only have one caliber/cartridge that does not have the correct head stamp. A 219 Donaldson Wasp and that I have in an old custom Winchester Highwall.
:cheers:
-JP
Click to expand...

Score!!

I’m always on the lookout for 9.5x57 (375 rimless express) brass, I build them from 8 and 9 x57, but sure would be nice to have properly stamped brass.
 
I finally got up to the range today to fire some new loads. Oddly, I ended up with better velocities with the 260gr partitions even with lighter charges of the H4350, then I got with the 235gr speers. I suspect due to more pressure expanding the case and sealing the chamber better maybe?

Initial firings, 70gr H4350 / 235gr Speer avg velocity 2180fps

Ladder (looking for pressure) H4350 / 260gr partition. I never did see pressure signs, but recoil with the old hard pad was stout the last few rounds.

68.5 - 2258
69.5 - 2378
70.0 - 2362
70.5 - 2415
71.0 - 2398
71.5 - 2416
72.0 - 2427

Ladder (finding pressure) H4895 / 260gr partition

60.0 - 2469
61.0 - I’ll explain (head scratcher)
62.0 - 2513
62.5 - 2546
63.0 - 2558
63.5 - 2570
64.0 - 2662
64.5 - 2653

Initial loading looking for the lands, I seated half way to the cannelure on the 260gr partition, cycled the cartridge in the rifle (outside) but didn’t hit the lands, bolt closed smooth. Figured I’d seat to the cannelure which puts the base of the bullet at about the base of the neck. Shot 61gr was a misfire, waited 15 seconds and ejected the cartridge, but the case came out with no bullet, and was easy to eject. I tapped the rifle on the butt on the bench, but had to get a cleaning rod to tap the bullet out of the lands. It wasn’t stuck tight, just a light tap and the bullet came out. Odd that I didn’t touch the lands when I took it outside to chamber that longer round.

What I find really odd, is the powder is stuck in the case, like it has/had moisture in it. All my other loads I shook and could hear loose powder like normal. Never in my life have I seen this or had it happen, my loading area is in a pretty dry environment. I checked the can of H4895, looks good as new still.

The case wasn’t full at 61gr, the powder is stuck in the case, as it would lay when the round was chambered (I’ll attach a photo). There was no bang or pop or smoke/smell. Iv tapped the case pretty good on its mouth, it’s stuck in there.

Every other round chambered and fired as should, I did find the H4895 a bit easier on the shoulder I think, or maybe it was just numb by then lol.

Defiantly solved my soot issues here though! Thanks a bunch fellas, next I’ll load some H4895 at 63gr and do some bear huntin :)

 
WhelanLad said:
post some photos of the full rounds, looks liek a cool cartridge!
more pics !!
an the gun
Click to expand...

Cheers WhelanLad, since you asked, I’ll give the story on this rifle…

In 1959 when the bison hunt was reintroduced in the NWT, my grandad and his partner were 2 of the first 30 people to hold tags (first 2 to harvest buffalo). Grandad packing his new’ish model 70 .375 h&h, his partner packing the newly developed .338wm, I believe also model 70) with “silver tip bullets”, the story goes.

I was only a kid when he’d tell the story, but when Bill shot his bison with the .338, it soaked up a couple magazine fulls of lead, but was still very much alive, and in full charge. Grandad was able to put one between the eyes and stop the charge, at only 20 yards infront of them.

Upon examining, they found not one of the .338 silver tips made it through the muscle into the vitals. I do not know/remember what he said the bullets looked like, mushroomed or not, or blew apart, im not sure.

With grandad being a gunsmith though, and addicted to big bores and wildcats, he decided to try improving the .338 case, with a .375 bullet.

This is right about the same time the Chattfield Taylor came into play, im not sure if he copied the CT, or came up with his own. He called it the .375 short magnum during my 18 years of having him around ( he passed in ‘98), the barrel is stamped 375-338 R.C.B.S.

I don’t know the barrel make, but he did do the works from a barrel blank (according to my dad), and the bluing and hand carved stock. When he passed in ‘98, this rifle went to my grandmas brother, but last fall it found its way over to my safe. It came with a box of mixed rounds, 225gr Hornady’s, 235gr speers, and some what I think to be 300gr lead. Iv fired the 225’s and 235’s, and am now figuring out a load for it, that’s more manageable for my thin shoulders, vs grandads beef shoulders lol.

The rifle has many moose and bear, and an Africa safari under it. I plan to carry on its journey, I may even see if I can get a mountain goat under it this year.


.375 h&h - .375-338 (not yet fire formed looks like) - 9.5x57 (.375 rimless nitro express)


I believe to be a 300gr bullet maybe?



My grandmother, tried claiming grandads new model 70 shortly after he bought it, so he bought her one in 1958, chambered in. .375h&h. I never got to meet this gramma, but when grandad passed in ‘98, I inherited her rifle. It’s a pretty humble feeling to have both of their .375’s in my safe.


 
Last edited:
You must log in or register to reply here.
Back
Top Bottom