I have a Yugo underfolder, with the nut on the side of the receiver that holds the stock to the receiver. If you have this type of AK, you know what I'm talking about. I believe it's referred to as a "castle nut". There appears to have been a roll pin or some type of pin that is inserted through the nut to keep it tight. This piece has fallen out, and now my whole stock wiggles and must be hand tightened repeatedly. Does anyone know what I need, in order to fix this, and where I could procure parts, including dimensions so I can get a replacement. It makes my AK basically un-shootable.