I got an issue with the height weight of the Rotary Autocannon. I can't mount them on any lighter vehicle like a truck without experiencing an enormous loss of grip on the wheels, the weight of the weapon throws the vehicle around.
The Rotary Autocannon weights 400, the same as a large Diesel Engine! Visually and logically not comprehensible.
BUT I understand that you want to balance the high destruction potenial of the cannon with the weight, and also enable players to built Warthog Planes and AA guns.
So here is my suggestion:
Please add a lighter version of the Rotary Autocannon. Same Barrel, smaller body, 1/4-1/2 the weight of the original cannon, less firepower (I don't know if there is a value in the cannon to reduce the impact of the projectiles, maybe reducing the fire rate is also doing the trick).