How to destroy objects only when they collide with other objects?

I have done a gun that automatically fires bullets every “update”. The problem I’m having is when I added the script:

void OnCollisionEnter()
{
Destroy (gameObject);
}

the bullets collide with each other and disappear. Is their a way to make it disappear only when it collides with objects other than the bullet?

Any help is very much appreciated.

Edit>Project Settings>Tags and Layers

Add new tag named bullet
set tag of your gameObject with the collider to bullet

void OnCollisionEnter(Collision collision)
        {
            if(collision.collider.gameObject.tag != "bullet")
            {
                Destroy(gameObject);
            }
        }

Other option:

Edit>Project Settings>Tags and Layers
Add new Layer named bullet and set your bullet with llayer bullet

Edit>Project Settings>Physics

Uncheck square bullet/bullet.
Now, colliders with layer bullet, dont have collision with other gameObjects with layer bullet