The .338 Lapua Magnum (8.6×70 mm or 8.58×70 mm) is a rimless, bottlenecked, centerfire rifle cartridge. It was developed during the 1980s as a high-powered, long-range cartridge for military snipers. Due to its use in the War in Afghanistan and the Iraq War, the cartridge has become widely available.
The loaded .338 cartridge is 14.93 mm (0.588 in) in diameter (rim) and 93.5 mm (3.68 in) long. It can penetrate better-than-standard military body armor at ranges of up to 1,000 meters (1,090 yds) and has a maximum effective range of about 1,750 meters (1,910 yds) with C.I.P. conforming ammunition at sea level conditions. Muzzle velocity is dependent on barrel length, seating depth, and powder charge, and varies from 880 to 915 m/s (2,890 to 3,000 ft/s) for commercial loads with 16.2-gram (250 gr) bullets, which corresponds to about 6,525 J (4,813 ft⋅lbf) of muzzle energy.
British military issue overpressure .338 Lapua Magnum cartridges with 91.4 mm (3.60 in) overall length, loaded with 16.2-gram (250 gr) LockBase B408 very-low-drag bullets fired at 936 m/s (3,071 ft/s) muzzle velocity from a L115A3 Long Range Rifle were used in November 2009 by British sniper Corporal of Horse (CoH) Craig Harrison to establish a new record for the longest confirmed sniper kill in combat, at a range of 2,475 m (2,707 yd) (since broken). In reports, CoH Harrison mentions the environmental conditions at Musa Qala were perfect for long-range shooting: no wind, mild weather, and clear visibility.
In addition to its military role, it is used by hunters and civilian long-range shooting enthusiasts. The .338 Lapua Magnum is capable of taking down any big game animals, though its suitability for some dangerous game (Cape buffalo, hippopotamus, white rhinoceros, and elephant) is arguable unless accompanied by a larger “backup” caliber: “There is a huge difference between calibers that will kill an elephant and those that can be relied upon to stop one.” In Namibia, the .338 Lapua Magnum in the past was legal for hunting Africa’s big five game if the loads had at least 5,400 J (3,983 ft⋅lbf) muzzle energy. Nowadays Namibia and other sub Saharan countries generally require larger minimal bore diameters by law for big five hunting.
