This is the G83 HGC, a prototype turret mounted in the TM34 hull, using the enormous M200 cannon based on naval ones. I've built +/- 2 weeks ago.
(It's the last using my existing hulls, the next tank will be more interesting, spoiler: an modified E 75)

Let's start with the basic, controls are Pitch and Roll, switch to the "Gunner" camera to control the turret.

The 200mm M200 Heavy Cannon fires explosive rounds, with 22 seconds of reload, and has only 10 shells. (It has an hud showing the ammo count, just a thing i tried to add to see if looks cool).

The aiming arc is 140°, 70° for each side, 9° of elevation and 7° of gun depression, the turret turns slowly.
It has an machine gun with 360° of rotation on the top.