problem with collision detection

my scene is, my player shoots prefab (bullet) and when it hits an object with tag name blocks the prefab has to get destroyed.i ahve added rigid body component for the prefab and checked on istrigger on another object which is in the bullet's path. the problem is i dont see any collision detection when the bullet hits any object that has tag name blocks. the script is as follows.

using UnityEngine; using System.Collections;

public class projectile : MonoBehaviour {

 public float projectileSpeed = 2f;

 // Use this for initialization
 void Start () {
 
 }
 
 // Update is called once per frame
 void Update () 
 {
     float amtToMove = projectileSpeed * Time.deltaTime;
     transform.Translate(Vector3.right * amtToMove);
 }
 
 void OnTriggerEnter(Collider otherobject) 
 {
    if(otherobject.tag == "blocks")
     {
         Debug.Log("iam hit");
     }
 }

}

need help...