Accuracy of tank coaxial MGs

[Amizaur]

I believe that accuracy of tank hull-mounted MGs is OK. They were used to fight infantrly at close and very close ranges, the mount was not fixed and wasn't very stable probably.
But the turret co-axial MG mounted - I suppose it was mounted very solid, and aiming was done trough main gun sight with scale to 1200m so it would seem that it was quite precise. The solid mounting would make it probably as precise as LMG if not a HMG ? Anyone knows ? Shouldn't it have less dispersion ? Would ease aiming the main gun at close ranges sometime too.

And would it be a problem from technical point of view to change globally the MG ammo from all tracers to 1 tracer every few ordinary bullets ? Would look more realistic and probably less gfx calculations for the game ?