This is a fairly old video and this might have been already addressed and changed but I noticed in the M1151 HMMWV (Humvee) Reveal the mounted machine canopy gun moves way to quickly and jittery.
This is seemingly due to it being the raw mouse movement. I feel that it would make sense to add a limit to the speed and make it more realistic.
In this video you can see with the newer armored gunned canopy the turning is controlled through a lever meaning that quick jittery movement would not happen. The movement
is more like a tank than a simple mounted machine gun.
It will also be slightly overpowered if a mounted 50. cal with little recoil could turn instantly...