Angle calculation for raycast shotgun weapon ?

Hello, i am doing quake-like fps weapons with completely editable characteristics, and i am trying to make a spray like for shotguns. The bullets are raycast and the script is attached on the gun. The shoot function is called on the controls script on the player. However, it fires on a straight line on the X axis and i cannot figure why. What i want is that the angle isn't that messed up and fires like a cone. Here's the script :

using UnityEngine; using UnityEngine.Networking;

public class GunScript : MonoBehaviour {

 //Bullets characteristics
 [SerializeField]
 private LayerMask mask;                     // the masks for the raycast
 private GameObject parentOfGun;             //the player that carries the gun
 private string weaponName = "Test Gun";     //The name of the gun that this script is attached
 private float damage = 2.5f;                  //How much damage a bullet deals to another player
 private int bulletsPerShot = 5;            //Useful for shotguns : how much bullets are raycasted at any shot.
 private float shotsPerSecond = 1;           //How many times the gun is activated per second
 private float range = 100;                  //The range of our bullets
 private float dispersionAngle = 45;         //The dispersion angle of our bullets, 
 [SerializeField]
 private Transform bulletSpawnPoint;         //The points where raycast bullets "appears"
 private float countdownBeforeShooting = 0f; //Time before we can shoot again*

 [SerializeField]
 private GameObject[] impactBulletEffects;   //List of all bullet impacts, order should be like in MaterialScript 


 private void Start()                        //Intialize our variables, like usual
 {
     if(bulletSpawnPoint == null)            //We don't want to spawn something from nowhere, do we ?
     {
         Debug.LogError("GunScript : No bullet spawnpoint referenced!");
         this.enabled = false;
     }
     dispersionAngle /= 360;                 // We fix to a usable dispersion
     gameObject.name = weaponName;           //Anything should have its own name, even chocolate bread should be named "Chocolatine" in France!
     parentOfGun = GetComponentInParent<NetworkIdentity>().gameObject;
 }

 public void Shoot(GameObject shooter)
 {
     if (shooter != parentOfGun)
     {
         Debug.Log("The guy who used this function has tried to use someone else's gun? Is his client screwed up, or is he hacking ?");
     }
     else
     {
         if (countdownBeforeShooting <= 0)
         {
             GetComponent<AudioSource>().Play();
             for (int i = 0; i < bulletsPerShot; i++)
             {
                 RaycastHit _hit;

                 //Implementing bullet spread

                 Vector3 newDirectionToShoot = Vector3.Scale(new Vector3(Random.Range(-dispersionAngle, dispersionAngle) * Mathf.Cos(Random.Range(0, 2 * Mathf.PI)), Random.Range(-dispersionAngle, dispersionAngle) * Mathf.Sin(Random.Range(0, 2 * Mathf.PI)), 0),bulletSpawnPoint.transform.forward);

                 print(newDirectionToShoot);
                 
                 Debug.DrawRay(bulletSpawnPoint.position, newDirectionToShoot, Color.red, 4);

                 if (Physics.Raycast(bulletSpawnPoint.position, newDirectionToShoot , out _hit, range, mask))
                 {
                     Debug.Log("We hit " + _hit.transform.name);
                     //We hit something

                     //Let's do the impact effect


                     Debug.Log(transform.forward);
                     GameObject impactObject = GetBulletImpact(_hit.transform.gameObject);
                     GameObject impactParticle = Instantiate(impactObject, _hit.point, Quaternion.Inverse(transform.rotation),_hit.transform);
                     Destroy(impactParticle, 5);
                     
                     //Add damage to the guy

                 }
                 countdownBeforeShooting = 1 / shotsPerSecond;
             }
         }
     }
 }
 private void Update()                       //This void fixes our countdown
 {
     countdownBeforeShooting -= Time.deltaTime;  
 }

 GameObject GetBulletImpact(GameObject objectHit)
 {
     MaterialScript ms = objectHit.GetComponent<MaterialScript>();
     if(ms != null)
     {
         int material = ms.material;
         switch (material)
         {
             case 0: //meat
                 return impactBulletEffects[0];
                 break;
             case 1: //sand
                 return impactBulletEffects[1];
                 break;
             case 2: //metal
                 return impactBulletEffects[2];
                 break;
             case 3: //stone
                 return impactBulletEffects[3];
                 break;
             case 4: //wood
                 return impactBulletEffects[4];
                 break;
             case 5: //water
                 return impactBulletEffects[5];
                 break;
             default:
                 Debug.LogError(objectHit.name + " has no correct MaterialScript attached. However, a GunScript tried to access it");
                 return null;
                 break;
         }

     } else
     {
         Debug.LogError(objectHit.name + " has no MaterialScript attached. However, a GunScript tried to access it");
         return null;
     }
 }

}