@sabrnick I agree. The post was old, but i believe I saw it here somewhere, Just can't remember which thread.
@sergio1251 The point to the glitch is to get inside the barrier and kill the zombies before they break the barrier(when rebuilt) because the zombies will be oblivious to you until the barrier is broken. This is an old glitch, but it's been working for a long while now. As for ammo, you're gonna need another guy to get max ammos from outside the barrier to get more ammo.
"Found by my friend", NO your friend didnt find it, barrier glitches are old as my grandma, you just need to find window barrier that you can jump on and do lag switch, not hard.