Answer by doomprodigy

Writing a script to attach a decal to a wall and emit a dust cloud is simple.

var BulletHole : GameObject;
var Smoke : GameObject;

// Later on inside shoot function where the raycast hits something

    if(BulletHole) //Check if the object exists
    {   
        BulletHole.transform.position = hit.point;
        var rotation = Quaternion.FromToRotation(Vector3.up, hit.normal);
        var BulletHole : GameObject = Instantiate(BulletHole, hit.point , rotation);
        //Bullet Hole Stick Onto Object
        BulletHole.transform.parent = hit.collider.transform;
        var Smoke: GameObject = Instantiate (Smoke, hit.point , rotation);
    }

This script is part of my raycast shoot script here but it should work if your weapon works via collisions.

Peace, Aaron Lewis

PS: Sorry I couldn't help with your problem, If you had made a forum topic something like this would have come up.