In Afghanistan, as in Iraq, the United States hires armed contractors to help with security around bases. Unlike Iraq, in Afghanistan many of these contractors are Afghans, and they often use weapons left over from the 1980s war with Russia. Thus American troops often get a little history lesson, as some of the weapons used by the contractors are somewhat elderly. Of particular interest to U.S. troops is the Russian .50 caliber (12.7mm) machine-gun. Some of these are the DShK, 12.7mm, a design that entered Russian service in 1938. The Russian 12.7 round uses an almost identical bullet to the U.S., but the cartridge is 108mm (4.25 inches) long, versus 99mm (3.9 inches) for the American one.
The Russian 12.7mm machine-guns have many of the same ballistic characteristics of the Browning .50 and has gone through several redesigns. The original DShK was a 34 kg (75 pound), gas operated, weapon with a 600 rounds per minute rate of fire. It served through World War II. China still uses a lot of these, as the Type 54. Many DShKs and Type 54s remain in service around the world.
The 25 kg (55 pound) NSV entered service in the early 1970s. It was also gas operated, but had a rate of fire of 800 rounds per minute. The 25 kg (55 pound) Kord was introduced in 1998, and has a gas operated, rotating bolt, firing mechanism.
The 50 pound American M-2 ("Ma Deuce") .50 caliber has a slower rate of fire (500 rounds per minute), but this is preferred to a higher rate of fire because the large bullets each do a lot of damage to ground targets. A higher rate of fire makes the weapon harder to aim at ground targets. The Russians preferred the higher rate of fire because their saw their 12.7mm weapon mainly as an anti-aircraft machine-gun. American troops had more targets on the ground than in the air.