Almost done with my first build. Got a bcg today from a gt member, so I got it cleaned and oiled. I grabbed the charging handle from my Oly, went to drop it in, and it won\'t fit. The notches are good, the handle drops in, but won\'t move forward. I tried a quick clean and oil, even some dremel action. Tried the charging handle from a Colt, same thing. Whats next?