So when you are able to prestige you have th choice to unlock a permanent unlock. Hover over a weapon you want and select it as an unlock. Press start and back (Select button) (Button to bring out score board) at the same time. this unlock that item and the chance to do so again. I Tried to do it to prestige hopefully allowing me to prestige multiple times but I didn't do it at the right time. This is for sure a weapon glitch but possibly a prestige glitch?

Let me know if you get it to prestige