.338 Lapua Magnum

The .338 Lapua Magnum, also written 8.6x70mm, is a Finnish rimless, bottlenecked, centerfire rifle cartridge built for long-range military sniping. Its roots lie in a 1983 American program by Research Armament Industries to defeat layered body armor at about a kilometer; that effort failed when cases ruptured under pressure, and the Finnish ammunition maker Lapua, officially Nammo Lapua Oy, redesigned the case with a thicker, harder web and sidewall. Working with the rifle makers Sako and Accuracy International, Lapua produced the round that was registered with the C.I.P. in 1989 and later codified by NATO after Dutch Army procurement. It fills the gap between the 7.62x51mm NATO and the .50 BMG. Use in the wars in Afghanistan and Iraq made it widely available, and in 2009 a British sniper set a 2,475 metre combat record with it. Hunters and civilian long-range shooters use it too.