It’s going to be hard to help you without seeing the project. If the suicide test caps out then it’s not a leak – at least, up to the point that they kill themselves. So I’d guess there’s something happening when the projectile is involved that isn’t happening when they kill themselves. Or the leak is in the projectile code itself. Are you spawning a lot of them? What about effects when they hit or muzzle flashes? Try just shooting a lot and make everyone unkillable. And I don’t suppose in the editor’s World Outliner, the actor count keeps going up. That would be too easy.
We should take this out of the forums. Message me.