Unity 5 Calling Function From Another Script On A Different Object

So I'm trying to get a function to run from a parent script when I click on an object with a particular tag. Script A (RayCastHit) is for my raycast and tests if it has hit the particular object while Script B(PickUpReactions) is for reducing a count. Script B is attached to the parent object while Script A is attached to the child.

using UnityEngine; using System.Collections;

public class RayCastHit : MonoBehaviour {

 public int PowerAmount = 1;
 public float fireRate = 0.25f;
 public float weaponRange = 50f;
 public Camera MainCam;
 public AudioClip ShotsFired;
 private float nextFire;

 void Start()
 {
     MainCam = GetComponentInParent<Camera>();
 }


 void Update()
 {
     if (Input.GetButtonDown("Fire1") && Time.time > nextFire)
     {
         nextFire = Time.time + fireRate;
         Vector3 rayOrigin = MainCam.ViewportToWorldPoint(new Vector3(0.5f, 0.5f, 0.0f));
         RaycastHit hit;
     if (Physics.Raycast(rayOrigin, MainCam.transform.forward, out hit, weaponRange))
         {
             if (hit.transform.gameObject.tag == "Generator")
             {
                 gameObject.GetComponent<PickUpReactions>().ReduceCount();
                 AudioSource.PlayClipAtPoint(ShotsFired, transform.position);
             }
         }
     }
 }

}

but because of the "gameObject.GetComponent().ReduceCount();" line, it comes up with the error "NullReferenceException: Object reference not set to an instance of an object RayCastHit.Update () (at Assets/Scripts/RayCastHit.cs:41)". he other script looks like this.

using UnityEngine; using System; using UnityEngine.UI; using System.Collections;

public class PickUpReactions : MonoBehaviour { public int count;

 void Start () {
     count = 0;
 }

 public void ReduceCount()
 {
     if (count >= 0)
     {
         count = count - 1;
     }
 }

} I've spent hours googling solutions that don't work yet so I don't know why they don't want to talk.