A quick visual guide to four major Soviet/Russian AK variants.
The AK-47 Type III is the first major production variant of the AK rifle. Due to difficulties with the stamping process that was originally intended to be used for AK production, this variant utilizes a milled receiver. Chambered in 7.62x39mm.
The AKM is the main AK variant produced and utilizes a stamped metal receiver, allowing for easier and cheaper production. Chambered in 7.62x39mm, the AKM entered service in the 1950s and has been produced in one form or another in such countries as the Soviet Union and Russia, Bulgaria, Romania, Hungary, Egypt, China, North Korea, and East Germany.
In the 1970s, the Soviet Union sought to modernize the Kalashnikov rifle and one of the major ways of achieving this was with the adoption of a new cartridge, the 5.45x39mm. Notable new features of the rifle also include the addition of a rather effective muzzlebrake and a 90 degree gas block (in contrast to the 45 degree gas block typically found on the previous variants).
An improved version of the AK-74 was introduced in 1991 as the AK-74M. This new rifle featured a new side-folding stock and an optics rail on the side of the receiver to allow the mounting of optical sights. Production of the rifle was also simplified, reducing the cost of the weapon. The AK-74M also serves as the basis for the AK-100 series of rifles and carbines produced by Kalashnikov Concern.
(When I started the Armed Anthros series as a replacement for the old Martial Pinups series, one of the things I wanted to do was to have an occasional post illustrating a few weapons of a given theme such as Kalashnikovs. I finally got around to getting one done and plan to do more going forward. These posts will not be anywhere nearly as in depth as the regular Armed Anthros pics, but I thought they might be handy as comparisons of certain weapons. I hope you enjoy!)