Hi everyone.
I have made a Niagara System for shell ejecting when the weapon is firing.
So basically the niagara spawns 1 empty shell mesh, adds velocity, gravity and collision to it.
It all works finem except that each time a new shell mesh is spawned, a velocity is added to all other already spawned meshes too. Which is much more noticeable in slow-mo, because previously spawned shell meshes start jumping on the ground 
How to solve this?