The DShK is first seen being used by the Cuban guards of Castro against Alex Mason and his team in the level, "Operation 40". It 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.
As for Spec Ops, players in Juggernaut suits will be attacked by this weapon mounted on a vehicle turret in Toxic Paradise, and the weapon can be found and used as an emplacement in the DLC mission Negotiator.
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 center, spaced close to each other.