I am trying to increase my ammo

I have a bullet script that fires and damages the enemy which is this

using UnityEngine; using System.Collections; public class Gunhit { public float damage; public RaycastHit hitInfo; }

public class bullet : MonoBehaviour { public float delay=0.1f; public float damage = 1.0f; private bool readyTofire = true; public AudioSource gunshot; public ParticleSystem muzzleFlash; public float ammoCount = 30f; // Update is called once per frame

 void Update () {
     gunshot.GetComponent<AudioSource>();
     muzzleFlash.GetComponent<ParticleSystem>();
     muzzleFlash.enableEmission = false;
     
         if(Input.GetMouseButtonDown(0)&& readyTofire&&ammoCount!=0)
     {
         gunshot.Play();
         muzzleFlash.enableEmission = true;
          RaycastHit hit;
         Ray ray = new Ray(transform.position, transform.forward);
         if (Physics.Raycast(ray, out hit))
         {
             hit.transform.SendMessage("OnBullet",
          SendMessageOptions.DontRequireReceiver);
             ammoCount--;
         }
     }
 }

}

and an ammo script public class ammo : MonoBehaviour {

 public GameObject Shoot;
 public void onTriggerEnter(Collider collision)
 {
     if(collision.tag=="ammo")
     {
         Shoot.GetComponent<bullet>().ammoCount += 10;
         Destroy(collision.gameObject);
     }
 }

}

but when I collide with the object tagged ammo nothing happens can someone tell me what I am doing wrong.