.375 Weatherby Magnum

• Name —.375 Weatherby Magnum • Origin — USA • Type — Rifle • Designer — Roy Weatherby • Design Date — 1944 • Manufacturer — Weatherby • Production Date — 1945 • Variants —.375 H&H Magnum,.375 Ackley Improved • Parent —.375 H&H Magnum • Case Type — Belted, bottleneck • Bullet —.375 • Land —.368 • Neck —.402 • Shoulder —.492 • Base —.512 • Rim Dia —.532 • Rim Thick —.051 • Case Length — 2.860 • Length — 3.600 • Rifling — 1 in 12 • Primer — Large rifle • Bw1 — 270 • Vel1 — 2940 • En1 — 5181 • Bw2 — 300 • Vel2 — 2800 • En2 — 5223 • Bw3 — 235 • Vel3 — 3135 • En3 — 5125 • Test Barrel Length — 20 in • Balsrc — Barnes & Amber

The.375 Weatherby Magnum was designed by Roy Weatherby 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.

The.375 Weatherby was designed as a dangerous game cartridge. The cartridge is able to fire a 300 gr bullet at 2800 ft/s generating a muzzle energy of 5224 ftlbf 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.

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.375 in. 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.: • Illustration —.375 Weatherby Magnum dimensions - All dimensions in inches (mm) CIP recommends a 6 groove barrel with groove width of 3.25 mm, a bore Ø of 9.35 mm and a groove Ø of 9.55 mm. The recommended twist rate is one revolution in 305 mm. Case capacity is 105 gr. of water (6.82 cm 3). The FreeBore/Leade for this Cartridge is 0.373 thou. as per the Factory Spec's.

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 240 ft/s and an increase in maximum point blank range of about 25 yd with bullets of equal weight. The.375 Weatherby Magnum fires a 270 gr at 2940 ft/s generating 5181 ftlbf and a 300 gr at 2800 ft/s which generates 5224 ftlbf. The cartridge generates more energy than factory loads for the.375 Remington Ultra Magnum,.416 Rigby or the.458 Winchester Magnum.