Smooth moving bullet

Hello,

I am making a 2-d top down shooter, and at the time I am only using unity gameobjects.
A cube looking bullet is being instantiated and is added velocity with:

rigidbody.velocity = transform.forward*BulletSpeed;

The problem is - it leave a small trail, it looks like bullet object from previous frame is being reneder with 40% transparency, while current frame is rendered well. The bullet takes about 2 seconds to go across the screen so i don’t think speed is the problem.

Bullet gameobject is a rigidbody with a constraint on y axis, a red color material and a box collider.

How many frames are you getting? And why is it contrained? I would just disable the gravity for the bullet?

I have no clue to why it is “Lagging”.