I recently put a replacement tapco tactical stock on my Chinese sks and when i originally put the top forehand on I had a little trouble pushing down the rotating pin to hold it down. I took it shooting this weekend and after roughly 30 rounds thru it the pin popped up and I can't get it back down. I've looked at it and the top cover isn't all the way down which is blocking the pin from rotating and holding the cover down. Is there any way I could fix this without sending it to a gunsmith? I have stopped firing the gun because I don't want to risk breaking the gun. Anything will help, thanks.