The AK-47 (or Kalashnikov) is a selective fire, gas operated 7.62mm assault rifle developed in the Soviet Union by Mikhail Kalashnikov in the 1946.
The designation AK-47 stands for Автомат Калашникова 47 (Avtomat Kalashnikova 47) - Kalashnikov automatic rifle, model of 1947.
The AK-47 was one of the first true assault rifles and, due to its durability, low production cost and ease of use, the weapon and its numerous variants remain the most widely used assault rifles in the world — so much so that more AK-type rifles have been produced than all other assault rifles combined.
The standard AK-47 or AKM fires the 7.62x39mm cartridge with a muzzle velocity of 710 metres per second (2,300 ft/s).
The AK-47 and AKM, with the 7.62×39mm cartridge, have a maximum effective range of around 400 metres (1,300 ft).
Comparison of the AK-47 and M16
Firing mode
The AK-47 allows the operator to select semi-automatic or fully automatic mode. The AK-47's fire selector lever is located on the right side of the receiver. The top-most position is safe, the middle is fully automatic, and the bottom is semi-automatic.
Reliability
The AK-47 has always enjoyed a reputation of rugged reliability. It is gas operated, using the gas from the barrel to push a piston attached to the bolt carrier, thus operating the action. The gas tube is fairly large and is visible above the barrel with ports or vents to allow the excess "dirty" gas to escape without affecting the action. The AK-47 is often built with generous clearances, allowing it to function easily in a dirty environment with little or no maintenance. While these clearances may not greatly harm accuracy, they certainly do not contribute to it either. It is very simple to disassemble and clean, and easily maintainable.
Accuracy
The AK-47 is a less accurate rifle than the M16. The difference in accuracy is primarily due to the slower muzzle velocity and a shorter distance between the sights of the AK-47.
http://en.wikisource.org/wiki/AK-47_Operator's_Manual
Best weapon ever..!! 
