What about a .375 Wby?

[EfRed]

I enjoyed reading this thread because I just purchased a 375wby and can’t seem to find any load data on it. Was wanting to shoot the 300 gr A-frame or possible a 350grainer. What powders are you guys using in this caliber? I was gonna try the IMR 4451 suppose to be similar burn rate to h4350.

On Midway USA, I think you can still get two reloading manuals for all the Weatherby cartridges. Of course, they're old. Data likely interchangeable with .375 Ackley Improved.

 

[EfRed]

I would think that with handloading the HH comes close to the (375) Wby. That, and it's unnecessary (the HH velocity is already considerably higher than comparable larger bore guns.) I recall getting 2,800 fps out of 270 gr handloads in the HH. That and where are you going to find brass and ammo for that (outdated, old, unpopular) Wby (it's all 378s now.) Lose your ammo on a flight and you'll have to use HH (as that's all you'll find in-country.) You MIGHT find Wby in AK. No significant difference...
View attachment 523792

If you lose your ammo, you can shoot 375 H&H in the 375 Weatherby. The ammo availability issue cuts no mustard.

 

[EfRed]

Here is a picture of Nick, bottom right with a couple of his old hunting buddies. Does anyone recognize some of the faces ?

View attachment 550184

I see Elmer Keith there, with the hat.

 

[EfRed]

EfRed said " On the other hand, a Mark V rifle was never made that had a 3 position safety, you MUST unload them through the bottom of the magazine to guard against accidental discharge. I know of two instances where a Wby went off "by itself" when being unloaded by cycling through the chamber."

It amazes me that so many folks don't know how to unload a bolt action rifle without incurring this risk. Whether push feed or CRF, simply run the bolt back and forth without turning the bolt handle down. Its that simple ! No need to fully turn the bolt into battery, just elevate the muzzle, roll ejection port downwards, and push bolt forward to strip rounds out of the magazine. Generally no need to even push bolt more than half the way forward, just until round pops free of feed lips, then withdraw bolt and round will fall out in hand. Repeat until magazine is empty. No risk of an ND when done this way.

....but I think the Weatherby Mk V is a cock-on-opening action, so the rifle will be cocker while you're doing all this back and forth. Not sure it's any safer. Weatherby manuals do caution to unload through the bottom.

 

[Jim Golden]

I use the 91.5gr of RL-22 in mine. I have a longer than standard barrel and get quite a bit more velocity than this. Chronographed 2885 and 2889 ft/s with a 300gr.

For some reason the image is sideways, but it opens right side up when I click on it.... This is from A-Square's manual.

 

[Riflecrank]

I was taking notes from Nick Harvey back in the 1980s too.
My first "custom" rifle was a Whitworth Mark X .375 H&H re-chambered to .375 WBY MAG,
and first hunted with in a bare fiberglass Brown Precision stock with the mould lines showing:

Perfect Kodiak deer rifle.

I have since had a Winchester M70 Stainless Classic re-chambered to .375 WBY MAG
as well as a CZ 550 Magnum.
The Winchester M70 is the most accurate "big bore" rifle I have ever fired.
It used the CIP homologated chambering reamer of 2002 revision.
The 6.5 Creedmoor has a throat like the .375 WBY MAG of 2002 scaled down to caliber.
The old original .375 WBY MAG of 1944 had a way longer parallel-sided throat, too long, even for me,
as it is not a long-leade-only throat like on the .458 WIN MAG.

My old original .375 WBY MAG is still in the safe, beside the other two, however.
Definitely go with a CIP 2002 reamer if re-chambering a .375 H&H to .375 WBY MAG.

So the .375 WBY MAG factory ammo gets 300-gr Nosler Partitions up 2800 fps in a 26" barrel.
2740 fps in a 24" barrel.
Easy to duplicate with H4350 and any 300-grainer you like.
That is about a 200 fps advantage over factory .375 H&H ammo with 300-grainers.

The .375 WBY MAG will have a greater advantage with 350-grainers.
Whatever MV the .375 H&H can do with 300-grainers, the .375 WBY MAG can do with 350-grainers.
Use H4831 SC with 350-grainers in the .375 WBY MAG.

I sighted my .375 WBY MAG 300-gr Nosler Weatherby factory ammo 3" high at 100 yards.
The .375 H&H 300-gr Swift A-Frame Remington factory ammo was then dead-on at 100 yards
when fired in the same rifle and scope setting.
No loss of accuracy.
Just lost about 100 fps for the H&H ammo in the WBY chamber.
Less recoil.
More deadly at lower velocity according to Doctari.
Pretty handy.

I may seem a bit schizophrenic on my two favorite cartridge choices.
The SAAMI/CIP .458 WIN MAG beats the SAAMI/CIP .458 Lott in my mind and in reality with handloading, if not factory ammo.
The CIP .375 WBY MAG beats the .375 H&H with both factory loads and more so with handloads.

 

[Riflecrank]

There was a reference earlier in this thread to .375 WBY MAG having a higher MAP than the .375 H&H. True, but not so big a difference as was stated.
CIP is the only standard I am aware of for the .375 WBY MAG.
This is how they homologate them:

.375 H&H: 4300 bar = 62,350 psi (MAP)

.375 WBY MAG: 4400 bar = 63,800 psi (MAP)

That is a 100 bar difference = 1,450 psi

If SAAMI allows 62,500 psi MAP for the .375 H&H, the difference is less than 90 bar.
Only 90 to 100 bar difference between the two, but what is ten or a hundred atmospheric pressures at sea level difference among good friends like the H&H and the WBY, eh ?

 

[Rifleman97]

If I recall correctly, someone said they got it to group fine in a 1:10?? In all honesty, I can't remember who this was or even if it was 1:10, so not particularly reliable. That being said, it's probably worth building a custom FA to utilize these missiles, if one is going to use it regularly.

Because weight has nothing to do with twist rate, all that matters is length. If it’s a flat base with lead it’s going to be a lot shorter than a high BC solid copper, and being shorter require a less aggressive twist rate. I’d guess 1:10 based on the 220gr round nose being stable in 30-06 at 1:10, but 200 solid copper high BC not being stable. Same thing with 120gr partition being stable in 257 wby, but the heaviest gammer that stabilizes in it is only 92 grains.

I could go on, but you get the point, without knowing the exact length you can’t accurately tell the stability. But I wouldn’t be surprised if 1:10 stabilized it fine, or at least marginally stable.

 

[colorado]

Yes the 300g A-Frames group fine in my 1 in 10" twist 375 Weatherby out of both 375 H&H ammo (2500 fps) and 375 Weatherby ammo (300g at 2800 fps). Also the Woodleigh 350g HD SP ammon at 2550 fps groups very well too.