.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. It was used in the War in Afghanistan and the Iraq War. As a result of this, it 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 metres (1,090 yd), and has a maximum effective range of about 1,750 metres (1,910 yd) 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.
!n addition to its military role, it is increasingly used by hunters and civilian long-range shooting enthusiasts. The .338 Lapua Magnum is capable of taking down any big game animal, 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 is legal for hunting Africa’s big five game if the loads have at least 5,400 J (3,983 ft⋅lbf) muzzle energy.