bullet collision with Terrain and Character Collider doesn't work in very fast speed

my bullet collider is Box Collider and set velosity with this method

bullet.rigidbody.velocity = bullet.forward * 300;

bullet collision with terrain doesn't give me correct point it's a little floating 1~2 meter, but when change speed with 30 (instead 300), it gives me correct poing in OnCollisionEnter method

There is another problem too

bullet does't collide with enemy (only Character Controller, not any Colliders on enemy) when enemy is far from player

I try to set bullet Box Collider both properties but doesn't resolv my problems

Collision Detection set Continuous and Continuous Dynamic

Thanks