I'm about to go to home depot and need info on the bolt that is used on the US palm battle grip. I have to get it off but cant remember what size (allen?) tool I need to get that thing off. I can't find anything in my tool box. Also, I just got a rpb industries polymer butt stock and will have to get a new tang screw to attach it. My tantal's mini screw is waaay too small. Any suggestions???