GameObject variable not holding it's value

So the variable of currentPrimary is not holding the GameObject that it is supposed to. When I run my game it prints out the correct GameObject. However, when I call the ExchangeWeapons method the same variable prints out null. Update continues to print the correct GameObject while the ExchangeWeapons method will always print null. It is the same variable, so why am I getting two different values for it? By the way, ExchangeWeapons is being called from another script.

using UnityEngine; using System.Collections;

 public class Weapons : MonoBehaviour {
     public int rifleAmmo = 100;
     public int pistolAmmo = 50;
 
     protected string currentActiveWeapon;
 
     private Animator animator;
     private GameObject currentPrimary, currentAlternate;
 
     void Start() {
         currentPrimary = GameObject.FindGameObjectWithTag("Primary");
         currentAlternate = GameObject.FindGameObjectWithTag("Alternate");
         animator = GetComponent<Animator>();
         currentAlternate.SetActive(false);
     }
 
     void Update() {
         print(currentPrimary + "Update");
         if (Input.GetButtonDown("SwitchWeapon")) {
             SwitchWeapon();
         }
     }
 
     public void SwitchWeapon() {
         animator.SetTrigger("SwitchWeapons");
     }
 
     private void SwitchWeapon2() {
         if (currentPrimary.activeSelf) {
             currentPrimary.SetActive(false);
             currentAlternate.SetActive(true);
         } else if (currentAlternate.activeSelf) {
             currentAlternate.SetActive(false);
             currentPrimary.SetActive(true);
         }
     }
 
     public void ExchangeWeapons(GameObject newWeapon) {
         print(currentPrimary);
         if(newWeapon.CompareTag("Primary")) {
             currentPrimary.transform.parent = null;
         }else if (newWeapon.CompareTag("Alternate")) {
             currentAlternate.transform.parent = null;
         }
     }
 }