375 Weatherby still a wildcat?

22 September 2015, 20:11

RIP

Here is a table of dates of introduction of the Wby proprietary cartridges:

Note the .375 Wby dates back to 1947.
It had a throat about 0.7500" long for parallel-sided free-bore originally.
It was improved to .370" length of PS free-bore in 2001 when re-designed (for better accuracy, I say) and re-marketing in the Weatherby DGR Mark V.

The table below says .373" of throat length for .375 Wby, but I guess that includes the bevel down to free-bore at the case mouth of the chamber,
and does not include any of the leade:

There is not much contribution of leade to effective throat length because the .375 Wby throat is so tight.
PS free-bore diameter is only .0006" greater than bullet diameter.

I will see if I can find the CIP chamber minimums and cartridge maximums drawing ...

22 September 2015, 20:52

RIP

The C.I.P. "Belted Cases Drawings" section includes all the current Weatherby proprietary cartridges. There are 13 of them, a Baker's Dozen.
It starts and ends with Weatherby proprietary cartridges.
No 220 Rocket Magnum nor 228 Weatherby Magnum anymore:

"224 Weath. Mag." (very first listing of this section)
240
257
270
7mm
30-378
300
338-378
340
"375 Weath. Mag." (the page right after 375 H&H)
378
416
"460 Weath. Mag." (very last page of this section)

If you checked C.I.P. and did not find it, you did not look far enough, did not look in the right section.

I have the sections like this:

Flanged Case Drawings: 5.6x35R to 4 Bore Rifle
Rimless Case Drawings: 5.45x39 to 12.7x70 and .17 Libra to .505 Gibbs
Belted Case Drawings: 224 Wby to 460 Wby
Rimfire Case Drawings: 4mm to 9mm and .22 BB cap to .22 WMRF
Handgun Case Drawings: 5.45x18 to 11mm73 and 22 Picra to 50 AE
Shot Cartridge Drawings: 4 Gauge to 32 Gauge and 8mm to .410

At the bottom of each page of the drawings:
"Reproduction forbidden as well as in the form of extracts without approval of C.I.P."

Find your C.I.P. drawings, web link or hard copy, and check the "Belted Case Drawings" section,
right between the "375 H.& H. Mag." and the "378 Weath. Mag." pages.

The date on the .375 Weatherby Magnum drawings is "02-05-15" which is C.I.P. code for May 15, 2002.
Redesign by Weatherby in 2001, update of the 1947 version.

22 September 2015, 22:57

MuskegMan

A cartridge drawing I dredged up:

23 September 2015, 06:38

RIP

That is Ken Howell's drawing from page 297 of Designing and Forming Custom Cartridges and it is a good one.
That and the reamer drawing above will give all info needed, brass maximums and chamber minimums.
The brass should not have changed at all since 1947.
Only the throat on the chamber reamer is new as of 2001 by Weatherby. 2002 CIP certified.

Ken Howell's brass weight for the cartridge is for as if the cartridge is made of solid brass.
140 grains of water refers to how much water is displaced by that hypothetical solid brass cartridge.
1198 grains of brass displaces 140 grains of water.
Assuming standard conditions for water with specific gravity 1.0, then the specific gravity for the brass is: 1198/140 = 8.56

http://www.accuratereloading.com/375wby.html

That is an old link above, and the load data table no longer shows up for me (it was my data), whatever browser I try, but there is some good general info there.

Norma-made .375 Wby brass with proper headstamp is best. Holds + 111 grains of water.
Home-made from Hornady basic is second choice.
Winchester (WW) .375 H&H fire formed will do in a pinch, and .375 H&H factory fodder is an accurate hunting load in a pinch.

Rule of thumb:
Fire a 300-grain load in a .375 H&H rifle with 24" barrel and note velocity.
Good loads from factory or handloads will be around 2450 to 2550 fps range for the vast majority of rifles.

Rechamber that rifle to .375 Weatherby Magnum (CIP of 2002).

Now fire the same 300-grain .375 H&H load in the .375 Wby chamber: You will lose only about 100 fps for the 300-grain bullet.

Now fire the .375 Weatherby Magnum factory load (by Norma for Weatherby), or equivalent handload with H4350, in the .375 Weatherby chamber:
You will get about 200 fps greater velocity with the 300-grain bullet in the .375 Wby versus the .375 H&H.

Heavier bullets like 350-grainers give the .375 Wby even greater velocity advantage (about + 250 fps) over the .375 H&H.
Lesser velocity advantage comes with using lighter bullets, maybe only 100 to 150 fps with the 250-grainers and lesser weights.

The .375 Weatherby factory ammo standard is the 300-grain Nosler Partition at 2800 fps from a 26" barrel.
That is a good load that lives up to the claim.

28 September 2015, 10:12

416RigbyHunter

Thanks guys, I must have been searching the wrong section.
My freebore on my reamer is .500", not including the leade, I was trying to find when this was changed from the longer freebore length originally used.

Cheers.

29 September 2015, 03:54

Idaho Sharpshooter

Thanks RIP! This is too important not to be here.

Rich

30 September 2015, 13:35

RIP

Thanks, Rich, I don't know who is the loonier riflecrank, you or me?

01 October 2015, 01:35

RIP

Rich,
New Weatherby cartridge, a wildcat no more, almost as good as your .22/378Wby:

6.5/300 Wby, coming soon to an emporium near you:

http://www.americanrifleman.or...ge-and-mark-v-rifle/

I guess that will be CIP certified too.

08 March 2016, 06:18

eezridr

My particular rifle (stainless Model 70) 375 H&H reamed to 375 Wea. will do the 2800 FPS (factory 300NP) with a 24" pipe. Heck of a cartridge!

quote:
Originally posted by RIP:
That is Ken Howell's drawing from page 297 of Designing and Forming Custom Cartridges and it is a good one.
That and the reamer drawing above will give all info needed, brass maximums and chamber minimums.
The brass should not have changed at all since 1947.
Only the throat on the chamber reamer is new as of 2001 by Weatherby. 2002 CIP certified.

Ken Howell's brass weight for the cartridge is for as if the cartridge is made of solid brass.
140 grains of water refers to how much water is displaced by that hypothetical solid brass cartridge.
1198 grains of brass displaces 140 grains of water.
Assuming standard conditions for water with specific gravity 1.0, then the specific gravity for the brass is: 1198/140 = 8.56

http://www.accuratereloading.com/375wby.html

That is an old link above, and the load data table no longer shows up for me (it was my data), whatever browser I try, but there is some good general info there.

Norma-made .375 Wby brass with proper headstamp is best. Holds + 111 grains of water.
Home-made from Hornady basic is second choice.
Winchester (WW) .375 H&H fire formed will do in a pinch, and .375 H&H factory fodder is an accurate hunting load in a pinch.

Rule of thumb:
Fire a 300-grain load in a .375 H&H rifle with 24" barrel and note velocity.
Good loads from factory or handloads will be around 2450 to 2550 fps range for the vast majority of rifles.

Rechamber that rifle to .375 Weatherby Magnum (CIP of 2002).

Now fire the same 300-grain .375 H&H load in the .375 Wby chamber: You will lose only about 100 fps for the 300-grain bullet.

Now fire the .375 Weatherby Magnum factory load (by Norma for Weatherby), or equivalent handload with H4350, in the .375 Weatherby chamber:
You will get about 200 fps greater velocity with the 300-grain bullet in the .375 Wby versus the .375 H&H.

Heavier bullets like 350-grainers give the .375 Wby even greater velocity advantage (about + 250 fps) over the .375 H&H.
Lesser velocity advantage comes with using lighter bullets, maybe only 100 to 150 fps with the 250-grainers and lesser weights.

The .375 Weatherby factory ammo standard is the 300-grain Nosler Partition at 2800 fps from a 26" barrel.
That is a good load that lives up to the claim.