Riflecrank,
What velocities were you getting with the 375 WBY and the 270 & 300 grain Barnes TSX ?
The 375 WBY is an intriguing cartridge.


Originally Posted by Riflecrank
EdM,

Nice buffalo.
I sure hope that is a Wisner copy of the "African" Winchester rear sight
on a fine custom rifle,
and not one of those pot metal Remington rear sights.
Kind of hard to see.
Please show and tell more about that rifle.

350-gr TSX from a .416 RemMag, eh? How fast was that bullet going when it left the rifle ?

For comparison, keeping it .375 WBY related, I have a handload for the Barnes Original 350-grainer, and a few more tidbits.

Brass: .375 WBY formed from Hornady basic cylindrical H&H brass, trimmed to 2.850", and necks annealed.
Primer: Federal GM215M or F215 (same/same)
Powder: Norma MRP 90.0 grains
Temperature 50 degrees F
Bullet: 350-gr Barnes Original, BC = 0.370, SD = 0.356
5-yard velocity = 2563 fps
MV = 2575 fps
KE = 5153 ft-lbs
Accuracy: Just under 1.5 MOA for 3 shots at 100 yards, 24"-barreled Winchester M70 Classic Stainless rechambered from .375 H&H,

Same rifle, powder and other load specifics/conditions as above except with 300-grainer and 2 gr more powder:
92.0 gr Norma MRP
Bullet: 300-gr Sierra GameKing, BC = 0.458, SD = 0.305
5-yard velocity = 2742 fps
MV = 2752 fps
KE = 5045 ft-lbs
Accuracy: Just under 1.0 MOA for 3 shots at 100 yards.

Same day, same rifle, .375 Weatherby Magnum factory ammo, with COL = 3.565", containing 88.5 grains of unknown powder (N-204?):
Bullet : 300-gr Nosler Partition, BC = 0.398, SD = 0,305
5-yard velocity = 2734 fps
MV = 2745 fps
KE = 5019 ft-lbs
Accuracy: 1.0 MOA for 3 shots at 100 yards.

The Weatherby factory ammo claim of 2800 fps with 300-grainer in a 26" barrel is spot-on, compared to my 24" barrel.

Also of note:
The properly headstamped, Norma-made .375 WBY brass has a greater water capacity than brass made from W-W .375 H&H or Hornady basic.
111.5 grains H2O for Norma brass at 2.860" maximum length.
108.4 grains H2O for fire-formed W-W .375 H&H that comes out short at 2.832" after fire-forming.
108.2 grains H2O for the Hornady basic brass at trim-to-length of 2.850".

I later discovered that H4350 in the Norma brass with any 300-grain bullet preferred is the way to go for one bullet weight does all in the .375 Weatherby,
with better accuracy and top velocity.
I also discovered that the make of bullet used has a lot to do with accuracy of the rifle. Duh.