Damaging Enemy strangely not working.

I am trying to set up collision detection with the bullet prefab and the enemy. oddly when I shoot the enemy "Sometimes" the bullet will be deleted, other times it just goes right through (This is while firing consecutive shots). Regardless of what i tell it to do after detection a collision nothing happens really. I have a bullet prefab, a projectile script, and enemy script. the bullet has a sphere collider, and the enemy has a capsule collider.

Is something wrong with the script? Or do you have tips on settings i may have forgotten to apply on the gameobject's components?

 using UnityEngine;
 using System.Collections;
 
 public class EnemyScript : MonoBehaviour {
 
 
     public float currentHealth;
     public int life = 0;
     
     void OnTriggerEnter(Collider other) 
     {
         if (other.tag == "Bullet") {
             currentHealth--;    
             Destroy(other.gameObject);
         }
     }
 }



 using UnityEngine;
 using System.Collections;
 
 public class projectileScript : MonoBehaviour 
 {
     public Vector3 muzzleVelocity;
     public GameObject weapon;
     public GameObject muzFlash;
     public float TTL;
 
 
     
     public bool isBallistic;
     public float Drag; // in metres/s lost per second.
     
     // Use this for initialization
     void Start () 
     {
         if (TTL == 0)
             TTL = 5;
         print(TTL);
         Invoke("projectileTimeout", TTL);
 
 
         weapon = GameObject.Find("BulletSlot");
         var w = weapon.GetComponent<weaponScript>();
         w.clip--;
 
         Instantiate (muzFlash, transform.position, transform.rotation);
 
     }
     
     // Update is called once per frame
     void Update () 
     {
         if (Drag != 0)
             muzzleVelocity += muzzleVelocity * (-Drag * Time.deltaTime);
         
         if (isBallistic)
             muzzleVelocity += Physics.gravity * Time.deltaTime;
         
         if (muzzleVelocity == Vector3.zero)
             return;
         else
             transform.position += muzzleVelocity * Time.deltaTime;
         transform.LookAt(transform.position + muzzleVelocity.normalized);
         Debug.DrawLine(transform.position, transform.position + muzzleVelocity.normalized, Color.red);
     }
 
 
     
     void projectileTimeout()
     {
         DestroyObject(gameObject);
     }
 }