CPU particle systems are not cleaned during the play

In my shooter game player able to shoot with rate of 5000 round per minute (maximum). Of course every bullet will spawn at least one particle system when hitting obstacle. But i have noticed, that after 10 seconds of shooting my fps greatly drops down. Most time was spent on ticking particle systems.
Here is screenshots:


I’d shot 5000-10000 bullets, and took screenshot right after i stopped. “Particles” - is thouse particles, that my bullets making.


This how my particle system looks. “Kill On Complete” is true and “Emitter loops” is 1 for both emitters.


And this how I spawn particle systems. Call stack looks like that: BulletHitting->BulletSystemEvent->SpawnEmitter. In case of there IS network multiplayer, it not replicates. Only bullet spawn replicates, then this bullet will fly on other machines absolutely identicaly.


But when i stop playing, particles systems are disappearing! Their number falls to 0.
Why this number isn’t going down while i playing?