Interestingly, the ammo itself has a projectile range which takes priority over the tank's cannon range. Cars have longer range because the bullets don't have a range. This problem also exists for shotguns.
I'm not sure what's the correct way to handle this. I guess I can give all projectiles the max range, but need to think if there are unexpected edge cases.
The obviously correct way to handle this is to have the quality modifiers increase maximum projectile range when applied to magazines. If you want to utilize a high-quality turret, then you have to prepare equally high-quality ammunition for it.