First person object tracking help

Well at first I thought this was simple to do for a first person weapon in the BGE, For the weapon to track to an object tracked to the camera or something-

I tried parenting object after object to empty too empty and parenting the brackets with objects. Failed ha I tried a lot of different ways to try to do something similar to what this guy did in this video without python since he didnt use that either

But does anybody know a way I can do this.

If its simple then I will feel dumb but hey at least im trying-

Any help please-