7mm Weatherby Mag
The 7mm Weatherby Magnum is a potent rifle cartridge from the Weatherby firearms company, initially featured in their Mark V rifles. Developed by Roy Weatherby in the early 1940s, it was among the first cartridges introduced by Weatherby. Derived from the .300 Holland & Holland Magnum case, it is necked down to 7mm (.284) with a distinctive double-radius shoulder. The case design eliminates taper, allowing it to feed from standard-length actions like the .257 Wby Mag and .270 Wby Mag.
Although the 7mm Weatherby Magnum gained prominence in the early 1950s with increased availability of Weatherby rifles, the more widely popular 7mm Remington Magnum, introduced in 1962, shares similar ballistics. Despite being introduced 18 years earlier, the 7mm Weatherby Magnum, due to its case design, offers a slight ballistic edge over the 7mm Rem Mag. However, the Remington's availability in more affordable and widespread rifles contributed significantly to its enduring popularity.
Weatherby's initial 7mm rifles had 1:12" barrels, too slow for stabilizing heavier bullets. In response to the introduction of the 7mm Rem Mag with a 1:9 1/4" barrel twist, Roy Weatherby modified the twist to 1:10 for enhanced performance.