Can't instantiate bullets when calling shoot function in one script from another script.

Hello,

I have a problem that I have been struggeling with for too long, so I hope that you can come to my aid.

I am making a game with some friends and we are using Unity in 2D mode. We have a Weapon class that can shoot, and then we have an Enemy class that should use the weapon to shoot, so it calls the shoot() in Weapon, but for some reason it will not instantiate the bullets when doing it this way.

Class Shooter: The point of this class is to call pew() in the PewPew class.

 public class Shooter : MonoBehaviour {

 PewPew pewpew;

 // Use this for initialization
 void Start () {
     pewpew = gameObject.AddComponent<PewPew> ();
 }
 
 // Update is called once per frame
 void Update () {
     pewpew.pew ();
 }

}

Class PewPew: This class is the one that will instantiate the bullets and send them on their way, and it does do so, if I call pew() inside this class but when I call pew() from Shooter all I get is a bounch of errors.

 public class PewPew : MonoBehaviour {

 public GameObject bullet;
 float speed = 20.0f;


 // Use this for initialization
 void Start () {
 }
 
 // Update is called once per frame
 void Update () {
     if(!true) // If set to true, it will start spawning bullets
     {
         pew ();
     }
 }

 public void pew()
 {
     Debug.Log ("PEWPEW");
     Rigidbody2D bulletInstance = Instantiate(bullet, transform.position, Quaternion.Euler(new Vector3(0,0,0))) as Rigidbody2D;
     bulletInstance.velocity = new Vector2(speed, 0);
 }

}

I get the Debug.Log message whenever I call the function, so I know that I can get to it, but for some reason I just can't get it to instantiate the bullets when I call from Shooter.

Thank you in advance for any help you can provide.