The .375 Weatherby Magnum (9.5×73mmB) is a medium-bore rifle cartridge. The cartridge is blown out, improved and provided with the

Weatherby Weatherby, Inc. is an American gun manufacturer founded in 1945 by Roy Weatherby. The company is best known for its high-powered magnum cartridges, such as the .257 Weatherby Magnum, .270 Weatherby Magnum, .300 Weatherby Magnum, .340 Weatherby ...

double radius shoulder – given the Weatherby treatment – version of the .375 H&H Magnum. Unlike other improved versions of the .375 H&H Magnum like the .375 Ackley Improved, the .375 Weatherby Magnum is not a wildcat and existed as a proprietary cartridge until the CIP published specifications for the cartridge.

History

The .375 Weatherby Magnum was designed by

Roy Weatherby Roy Edward Weatherby (4 September 1910 – 4 April 1988), was the founder and owner of Weatherby, Inc., an American rifle, shotgun and cartridge manufacturing company founded 1945. Weatherby created an entire line of custom cartridges, and was ...

in South Gate, California, in 1944 and put into production in 1945. The original cases were fire formed from .300 H&H Magnum Winchester brass, then from Richard Speer's 300 Weatherby brass before finally settling with Norma as a source for cases. It was also with Norma that Weatherby finally found a source for loaded ammunition. Production of .375 Weatherby ammunition ceased in 1960 but was reintroduced in 2001 due to demand.

Comments

The .375 Weatherby was designed as a dangerous game cartridge. The cartridge is able to fire a bullet at generating a muzzle energy of with the trajectory of the 30-06 Springfield. This performance level makes it an appropriate all-round African safari cartridge that is usable against plains game species as well. The .375 Weatherby is considered overly powerful for North American game.

Design and specifications

The .375 Weatherby Magnum is an improved version of the .375 H&H Magnum. The parent case is based on the .300 H&H Magnum blown out and necked up to accept a . The cartridge features the Weatherby double radius shoulder. The Weatherby Magnum is not considered a proprietary cartridge as the CIP has published specifications for the cartridge. : CIP recommends a 6 groove barrel with groove width of , a bore Ø of and a groove Ø of . The recommended twist rate is one revolution in . Case capacity is 105 gr. of water (6.82 cm³). The FreeBore/Leade for this Cartridge is 0.373 thou. as per the Factory Spec's.

Performance

As an improved cartridge the .375 Weatherby Magnum provides a leap in performance over its parent cartridge. The velocity gain over the .375 H&H Magnum works out to be about and an increase in maximum point blank range of about with bullets of equal weight. The .375 Weatherby Magnum fires a at generating and a at which generates . The cartridge generates more energy than factory loads for the .375 Remington Ultra Magnum, .416 Rigby or the .458 Winchester Magnum.

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