)In 1974, shortly after the introduction of the 5.56mm NATO, the USSR began to issue a new Kalashnikov variant, the AK-74, chambered in the small-bore 5.45×39mm cartridge, which was a standard 7.62×39mm necked down to take a smaller, lighter, faster bullet.It soon became standard issue in Soviet nations, although many of the nations with export Kalashnikovs retained the larger 7.62×39mm round.