Set fire rate of a sentry gun

I have my sentry gun in the center of my scenes, it finds the player and starts to fire!
But at the moment it fires only 1 shot, and i want to shot at least 1 shot every second!
I used FPS unity tutorial to write the code but it doesn’t work on my game!
Here the code:

	public float reload_time = 1.0F;
	private float nextFire = 0.0

		if(Vector3.Angle(forward, targetDir) < shootAngleDistance && Time.time > nextFire){
			nextFire = Time.time + reload_time;

IEnumerator WaitAndFire(float delay){
yield return new WaitForSeconds(delay);
Fire ();
isFiring = false;
And…Into the update:

    if(Vector3.Angle(forward, targetDir) < shootAngleDistance && !isFiring){
		isFiring = true;