Buddy hit me with a question that I know nothing about, so I thought someone here could help. He has a Colt lower (large hole) and some other manuf. upper. At some point they put an offset pivot pin in there (DPMS, if it matters) and now he can't get it out. Says he has tried to hold one side and unscrew the other, but nothing happens. I have never laid eyes on one of those pins, so I don't know if it takes something special to remove. Any ideas? He wants to switch uppers on a couple of his AR's, but can't get this one apart.