The 375 Weatherby Magnum is one of Roy Weatherby's original cartridges, introduced in 1945. It is simply an "improved" version of the 375 H&H, blown out to remove body taper and increase powder capacity, with Weatherby's distinctive "double-Venturi" shoulder. Performance is greatly increased over 375 H&H; Weatherby factory loads (supplied by Norma) exceed 375 H&H ballistics by about 250 feet per second, flattening trajectory and significantly increasing energy yield (to well over 5000 foot-pounds). Recoil is also significantly increased, but the effect of the more energy is visible on the largest game. The 375 Weatherby Magnum and 375 RUM are essentially equal in performance, however the 375 Weatherby Magnum has the advantage of safely digesting commonly available 375 H&H ammo. Weatherby is the primary supplier of factory ammo and production rifles, but a 375 Weatherby Magnum can easily be created by rechambering 375 H&H rifles. —
Craig Boddington