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.

Be sure you go to onTriggerEnter. check isTrigger on And your player has rigidbody.