The Soviet Union released its 5.45x39mm cartridge in 1974 for use in their AK-74 rifle, which was modified from their AK-47. Following the example of the American 5.56mm cartridge, designed to be a replacement for the 7.62x51 cartridge, the Soviet 5.45x39mm was intended to be a replacement for the 7.62x39mm. A key difference between the cartridge of the Soviets and the cartridge of the U.S. is that Soviet designers needed only to modify a proven design (their AK-47) to have an established rifle which could fire the cartridge. The U.S., however, in adopting the 5.56x45mm cartridge, was switching to an entirely new rifle platform that had never been tested in battle.
The primary advantages to the conversion were a reduction in weight of the ammunition, as well as a noticeable decrease in recoil impact compared to the 7.62x39mm. Some recoil tests showed the 5.45x39mm generating a recoil of 2.5 foot pounds when fired from the AK-74. The 7.62x39mm cartridge, on the other hand, generates a recoil of about 4.5 foot pounds, depending on the weapon. This recoil is lower than what the 5.56mm generates, which is 4.75 foot pounds when fired from the M16. This figure is even more remarkable when you understand that recoil for the M14 when it fires the 7.62x51mm NATO cartridge, is just less than 15 foot pounds. As well as the reduction in recoil, the weight of the cartridge itself is greatly diminished in the 5.45x39mm. A soldier may have been able to carry 180 rounds of 7.62x39 into battle, but now he is able to hoist 270 rounds of 5.45x39 with no perceptible increase in weight.
The 5.45x39mm cartridge performance is impressive with the 49 grain powder load reaching muzzle velocities in excess of 3,000 feet per second and generating muzzle energies exceeding 1,400 foot pounds. Downrange accuracy is respectable, with 3.5 inch groups easily achievable at 300 yards.
Though manufactured primarily in Russia to combat specifications, Hornady also produces the 5.45x39mm in the United States. Hornady caps their cartridges with the polymer tipped V-MAX bullets with a load that boasts high levels of accuracy and can be successfully employed in hunting small game. Wolf Ammunition Company sells ammo capped with hollow point bullets, soft point bullets and full metal jacket bullets. Bernaul ammunition fires boat tail bullets, and they claim that their cartridges are accurate and consistent enough to form a group of one hundred shots in less than one inch at one hundred meters.
The 5.45x39 is not wildly popular in the U.S., but it has been chambered for rifles using the AR-15 platform as well as in a rifle produced by Saiga. The 5.45x39 will not likely trump the popularity of the 5.56 NATO cartridge in the US, but the low recoil and great accuracy have earned this Warsaw Pact veteran a deserved place in the American ammo market for many years to come.