[Garem]

Modern bullets move at about 900-1000 m/s (approx 4500 km/h) to way, way faster- up to 4000 m/s. And we're shooting futuristic video game bullets. The motion of a vehicle will not significantly impact projectile velocity, especially in a game that limits your range of view and distance of shots. We're not shooting artillery here.

Bullet physics don't need to be real in the game. Simple and believable is sufficient. Maybe better, since there will be thousands of these bad boys floating around and we don't need to add even more computations to the mess when those minute computations will have little to no impact on outcomes.