[rotorwrench]

Many of the wartime trucks just had metal bows to frame up the canvas top. With the side board hinged down, there would be no support for the bows. The top would have to come down anyway just to use the gun. The belt fed heavy machine guns would require at least a 2-man crew to operate it but it would be better served with further help to insure a constant feed of ammo. Some of the Soviet 12.7 HMGs had a snail type drum that could be attached but the belt feeding was added to make reloading easier and faster. The gun is much more versatile with that capability.

These guns were a counterpart of the Browning M-2 heavy barrel .50 caliber HMGs that were used by US and other allied forces. This size/caliber of HMG was very effective for any number of battlefield situations. The recoil is pretty heavy but not as bad as anything larger. A soldier would feel kind of naked standing up there & firing that DShK with very little armor protection but it would still be an effective weapon system. The hand crank was likely there so they could raise and lower the height of the gun if that is in fact a hand crank.