How would I go about making an animation affected by this script?

So I made an animation called "M1911Idle" and it is attached to the the arm holding it. It works, but when I use another script to "add weight" to the gun, like when you turn, the gun moves a bit, not just sit in one place. But, with the "M1911Idle" animation running, it doesn't work. How could I go about making this script work while the animation is playing?

Script: public var MoveAmount : float = 1;

     public var MoveSpeed : float = 2;
     
     public var GUN: GameObject;
     
     public var MoveOnX : float;
     
     public var MoveOnY : float;
       
     public var DefaultPos : Vector3;
     
     public var NewGunPos : Vector3;
     
 function Start(){
 
     DefaultPos = transform.localPosition;
 
 }
     
     
 function Update () {
 
     MoveOnX = Input.GetAxis( "Mouse X" ) *Time.deltaTime * MoveAmount;
     
     MoveOnY = Input.GetAxis( "Mouse Y" ) *Time.deltaTime * MoveAmount;
     
     NewGunPos = new Vector3 ( DefaultPos.x+ MoveOnX, DefaultPos.y+ MoveOnY, DefaultPos.z);
     
     GUN.transform.localPosition = Vector3.Lerp(GUN.transform.localPosition, NewGunPos , MoveSpeed * Time.deltaTime);
 
 }

Thanks.