The AK-47, officially known as the Avtomat Kalashnikova, is a gas-operated assault rifle that is chambered for the 7.62×39mm cartridge. Developed in the Soviet Union by Russian small-arms designer Mikhail Kalashnikov, it is the originating firearm of the Kalashnikov family of rifles. After more than eight decades since its creation, the AK-47 model and its variants remain one of the most popular and widely used firearms in the world.
AKMS with a stamped Type 4B receiver (top) and an AK-47 with a milled Type 2A receiver
Wound Profiles of Russian small-arms ammunition compiled by Dr. Martin Fackler on behalf of the U.S. military
The gas-operated mechanism of a Norinco AK-47
AK-47 barrel and its distinctive gas block with a horizontal row of gas relief ports
Gas-operation is a system of operation used to provide energy to operate locked breech, autoloading firearms. In gas-operation, a portion of high-pressure gas from the cartridge being fired is used to power a mechanism to dispose of the spent case and insert a new cartridge into the chamber. Energy from the gas is harnessed through either a port in the barrel or a trap at the muzzle. This high-pressure gas impinges on a surface such as a piston head to provide motion for unlocking of the action, extraction of the spent case, ejection, cocking of the hammer or striker, chambering of a fresh cartridge, and locking of the action.
Long stroke gas piston, from an AK-74
Short stroke gas piston and bolt carrier group, from a gas piston AR-15
