pick up ammo from specific gun?

Hello! Does anyone know how to do to collect ammunition for a specific weapon? (a box of ammunition that fills the bullets of an assigned weapon).
Thank you!

gun script:

 var speed = 10;//speed of bullet
 var ammo:Rigidbody;//ammo 
 var currentBullets = 0;//This is the amount RIGHT NOW that the gun has. (should be 0 by default.)
 var totalBullets = 30; //TOTAL amount the gun will have
 var readynow : boolean = true;
 var reloadammo : int = 30;
 
  function Update () 
  
  { 
 if(totalBullets >0) /////////// I addad
 {
  if(Input.GetButtonDown("Fire1")) 
  { 
  if (currentBullets > 0) //only shoot if you have ammo.
  {
  readynow = false;//can't shoot
  var ammoClone : Rigidbody = Instantiate(ammo, transform.position, transform.rotation);
  ammoClone.velocity = transform.forward * speed;
  yield WaitForSeconds(.1);// pause between shots
  readynow = true;//can shoot
   totalBullets--; /////////// I addad
  currentBullets--; //subtract one
  }
  else //if you have less than 1 bullet
  {
  //perform reload animation
  }
  } 
  }  /////////// I addad
  
  } 
  function LateUpdate () 
  {
  if(readynow)
  {
  Update();
   
  if(Input.GetKeyDown(KeyCode.R)){ 
  currentBullets = (reloadammo);
  readynow = true;
  }
  }
  }

You can use OnCollusionEnter and check for Tags for validating which ammo is for which guns and equip it.
Void OnCollusionEnter(Collusion other){

if (Other.gameobject.tag == "Ak-47")

//Pick Up

}