One of the main problems of the 100 is when you start having extraction failures. Usually lack of cleaning the chamber and gas system. When this starts to happen the extractor will pound out the groove cut in the bolt lips. We replaced lots of bolts when they were under warranty. A gauge of about .057 to check the space was used. I don;t know where you can get the bolts now. If someone has the original repair factory manuel on the 100's you might post the correct gauge dimensions. It has been over 30 yrs since I worked on these
Les
