How to destroy gun bullet clone?

ok so i have a rigged gun model and it shoots fine and the animation works fine but my bullets are spheres, i was going for more of an airsoft gun effect. but anyways how can i make it so the clones of the spheres get destroyed after so many are made, or something like that?

Well first you might want to destroy it after 5 seconds, right? So here is the way to do that in JS:

function Update () {
Destroy (this.gameObject, 5);
}

But you also might want to destroy it on collision, so here is how you would do that:

function OnTriggerEnter(){
Destroy (this.gameObject);
}

Just write these in an empty JS file and attach it to the object. And when you create these sphere clones, just instantiate a prefab of the sphere with this script attached.

However, do note that using actual collisions for bullets is not efficient and could cause problems on a large scale.