since patch 1.58 when the elevation angles for the mBT-52 Kuma were tweaked (clipping of main cannon over the engine deck) the kuma now has only -5° of gun depression over the front and sides.
However, the MBT revolution, which the Kuma is based off, has -9° of gun depression over the front and sides for the main cannon.
To keep the MBT-52 true to it's real life counterpart, the elevation angles of the main cannon should be tweaked to -9°/+20° over the front and sides of the vehicle.
And the elevation for the rear over the engine deck should be 0° as it still clips with some parts of the back of the vehicle