Problem with my Weapon Recharge script

Hi I am French and I use Google translation to speak in English good I explain my problem so when I shoot with my weapon its remove -1 has my charger and when I press "R" to recharge its me rema 15 Ammunition and its takes me -1 on my reserve until the all goes well but the problem is that when my reserve and lower has or equal to 15 when I recharge it takes away nothing from my reserve but its still remade me 15 ammunition in my charger so I'm sure it's a stupid mistake but I find no thanks for your help

using System.Collections; using System.Collections.Generic; using UnityEngine;

public class PlayerShoot : MonoBehaviour {

 public float ReloadDelay = 3f;
 public float ShotDelay = 0.25f;
 public int clip;
 public int maxclip;
 public int reserve; //45
 public GameObject BulletPrefab;
 public GUISkin ClipSkin;
 public AudioClip ShotSound;
 public AudioClip ReloadSound;
 public float VolumeAudio;

 private Vector3 Vector;
 private EnnemyScript ennemyscript;
 private float cooldownTimer = 0f;

 AudioSource Audio;



 // Use this for initialization
 void Start () {
     
     Audio = GetComponent<AudioSource> ();

     ennemyscript = GameObject.FindGameObjectWithTag ("Ennemy").GetComponent<EnnemyScript> ();

     Time.timeScale = 1;
     
 }
 
 // Update is called once per frame
 void FixedUpdate () {

     cooldownTimer -= Time.deltaTime;

     if(clip >= 1){
         if (Input.GetButton ("Fire1") && cooldownTimer <= 0) {
             Instantiate (BulletPrefab, transform.position, transform.rotation);
             Audio.PlayOneShot (ShotSound, VolumeAudio);
             ennemyscript.range = 15;
             clip -= 1;
             cooldownTimer = ShotDelay;
         }

     }


         if (Input.GetButton ("Fire2") && cooldownTimer <= 0) {


         }

     if (Input.GetKey (KeyCode.R) && cooldownTimer <= 0) {
         Audio.PlayOneShot (ReloadSound, VolumeAudio);
     
         if (reserve >= 15) {
             RemoveReserve ();
             clip += maxclip - clip;

         }

         if (reserve <= 15 ) {
             clip += maxclip - clip;
             RemoveReserve ();
         }

         cooldownTimer = ReloadDelay;

     }
         
     if (reserve <= 0) {
         reserve = 0;
     }

 }

 void RemoveReserve(){
     reserve -= maxclip - clip;
 }

 void OnGUI(){

     GUI.skin = ClipSkin;
     GUI.Box (new Rect(10, 740, 150, 25), clip+ " / " +reserve);

 }

}