DShK

The DShK (Degtyaryova-Shpagina Krupnokaliberny, Degtyaryov-Shpagin Large-Calibre) is a Russian heavy machine gun, comparable to the American M2. It is often referred to as the "Dushka" (Sweet, dear).

Call of Duty: Black Ops
The DShK is frequently seen in "Vorkuta", mounted on the back of trucks manned by prison guards. After jumping from his motorcycle to one of these trucks, Mason uses a DShK to fire at enemy motorcycles, trucks, and Mi-8 helicopters. During "Executive Order", the DShK is seen mounted on trucks, but never usable. During "WMD", Hudson and his team use a similar truck, with Hudson using the mounted DShK to provide cover while the truck is started.

Call of Duty: Modern Warfare 3
The DShK appears briefly in the Call of Duty: Modern Warfare 3 reveal trailer, mounted on the top of a T-90 MBT in Berlin. It is unknown if it will be usuable or not.

Trivia

 * The sights on this weapon are unique compared to other mounted machine guns featured in the Call of Duty series; the sight is a circle with the crosshair formed by a wire strung through a chain. It also has an unusable deflection-finding AA sight on the left side of the gun which uses three wires running horizontally through its centre, spaced close to each other.
 * This is the second time a featured Soviet Heavy Machine Gun has been usable by the player, the first time being the mounted RPDs in the Call of Duty 4 level "Safehouse".
 * This DShK, the MG42s in Project Nova, and the M60 in Crash Site share the same firing sound.
 * When firing, the ammunition belt does not move.