Why did the AK-47 become so popular?

From The Economist:

MIKHAIL KALASHNIKOV died on December 23rd, aged 94. But his 66-year-old invention, theAvtomat Kalashnikova, has plenty more shots left to fire. Developed in 1947 and first used by Soviet forces in 1949, the AK-47 assault rifle and its many derivatives are now used by the armed forces of more than 80 countries, and by freelancers in many more. No-one knows quite how many are in circulation: 100m is a reasonable guess. As a proportion of all the guns in the world—another number no-one can be quite sure about—Kalashnikovs probably make up more than one in ten of all firearms. Why does an ageing Soviet invention still dominate modern warfare?

The cultural impact of the AK is felt all over the world. Quentin Tarantino’s villains celebrate its appropriateness for “when you've absolutely, positively got to kill every [enemy combatant] in the room”. Mexican outlaws boast about their cuernos de chivo, or “goat horns”, the nickname given to the rifle because of its curved magazine. In some parts of Africa, where the gun is seen as a symbol of the ousting of colonial rulers, Kalash is a popular name for boys. Mozambique displays the gun on its flag. In Lebanon, a model nicknamed the “Bin Laden” sells for twice the price of the standard AK-47, because it is the type that al-Qaeda’s former boss was seen toting in some of his videos.

The gun is nothing special. Its controls are unsophisticated; it is not even particularly accurate. But this simplicity is a reason for its success.

More here.