In 1943 The Soviet Union adopted a new intermediate cartridge, the 7.62x41mm M43, and the first weapon chambered for it was the Simonov-designed SKS carbine, designed to replace the M91 Mosin-Nagant rifles in 7.62x54mm that had served since 1891. Having been impressed with the German Sturmgewehr rifles captured during WW II, the Soviets solicited their extensive cadre of arms designers to come up with an indigenous assault rifle design for this new Soviet cartridge. The favored design was by Sudayev, the successful Russian submachine gun designer. Mikhail Kalashnikov, a promising designer but relative newcomer, had an idea for a weapons family based on a single design. The idea was not new, but as it turned out, Kalashnikov was the first to make the idea work.
Kalashnikov submitted his idea and in early 1946 was advised to proceed with development of an assault rifle. He assembled a design team that created his design in prototype form, and although imperfect as all neophyte designs are, flaws were eliminated one at a time as it progressed through a series of prototypes, and his design for an assault rifle was officially adopted as the AK-47 (still in caliber 7.62x41mm) in June of 1949. With the model designation AK-47, came the introduction of the familiar safety/selector on the right side, which still appears on copycat designs such as the Israeli Galil and the South African R-4.
The first production models featured a formed sheet-metal receiver (Type I), as did the second (Type II), but when these proved unsatisfactory they were replaced in the Type III with a milled receiver machined from a solid forging that required 120 machining operations. As old ammo stocks were depleted, SKS rifles and AK-47 assault rifles were converted to and made in the current M43 round, 7.62x39mm. Metallurgical advances permitted a return to the sheet-metal receiver with the first major re-design, the AKM that was introduced in 1959.
From the onset, the Kalashnikov designs featured a long-stroke gas piston acting through a bolt carrier to turn a rotary bolt that held the extractor. They fed from a 30-round detachable box magazine, and in classic assault rifle form featured selective fire and a separate pistol grip for added control, and a relatively straight-line stock.
(Adapted with permission from The World’s Assault Rifles [Johnston/Nelson, 1200 pages, © 2010 Ironside International Publishers], available at: www.worlds-assault-rifles.net)