Found this (Dept of the Army Technical Manual) while searching out information about the M2 bipod. It has interesting information and illustrations on maintenance and some mods to M14 and M14A1.
http://www.scribd.com/doc/12891757/Vietnam-M14-M14A-M2-Bipod-Rifle
http://www.scribd.com/doc/12891757/Vietnam-M14-M14A-M2-Bipod-Rifle