The AK-47, aka the AK, derives its name from the Russian Автомат Калашникова; Avtomat Kalashnikova or Kalashnikov's Automatic Rifle. The 47 comes from the year the Soviet Union accepted the rifle for field testing / deployment. Developed at the end of World War II, it would be the main weapon of Soviet and Warsaw Pact forces by 1949.

The AK-47 is a semi-automatic gas-powered assault rifle, firing a 7.62×39mm cartridge and capable of 600 rounds per minute at a muzzle velocity of 2,350 ft/s. The magazine sizes were 10 – 75 rounds.

Mikhail Kalashnikov started weapon design in 1941 to help defeat Nazi Germany. Within 4 years, he had completed development of what would be the standard weapon issue for the Soviet Union.

The AK-47 was replaced in the Soviet Union by the AK-74 in 1974. The older AK-47’s were sent to Soviet Bloc countries and allies and are still in use today.

More Info: en.wikipedia.org