A few particles causing massive slowdown when destroyed?

I am working on a script to basically make a gun shoot particle bullets. So far it looks like this :

var projectile : ParticleEmitter;

function Update () 
   if (Input.GetButton ("Fire"))
         var bullet = Instantiate(projectile, transform.position, transform.rotation);
     bullet.localVelocity = Vector3.forward * 10;
     Destroy (bullet, 1);

In short, this instantiates particles that go forward and it destroys them after 1 second. After only 10 particles spawned and destroyed, the game drops from 1000+ FPS to 5 FPS. An "!emitter" error appears but I can't really figure it out. I also noticed that the FPS drop only occurs when the camera is looking at the area where the particles disappear.

What is going on?

Instantiating an entire particle system for every bullet entirely defeats the purpose of using a particle system in the first place. If you're doing that you would be better off using normal 3D objects. The point of using a particle system would be to have many bullets with one system. Also, your code is framerate-dependent since you have a bullet instantiated every frame. You'd want it to be time-based instead.