As above, the Jerry Kuhnhausen shop manual on the US Gas Operated .30 Caliber Service Rifles, M1 and M14 contains the most detailed info on how to accurize the rifles.
This was written as a training aid for new gunsmithing students and contains the most and most detailed info there is about the rifles and how to gunsmith and accurize them to National Match standards.
If you want to do it right, this shows how it's done.
http://www.brownells.com/books-video...prod25718.aspx