So idk what the title should be, I'm making a gun and everything works, but the bullet flys the same way no matter the bullets rotation, I did Bullet.Velocity = Vector3.new (10,0,0)
While I don't recommend using Velocity for bullets, here is the answer to your problem.
Instead of assigning a Vector3 value to the Velocity, give the lookVector of the bullet, multiplied by the speed you want your bullet to travel. Example:
bullet.Velocity = bullet.CFrame.lookVector * 100
Make sure you do this before assigning the bullet's parent.