I like Kuhnhausen's shop manual on the M1icon Carbines. It's full of information on parts inspection and shows all the critical dimensions and measurements. Also very good on the critical differences between commercial carbine parts and genuine USGI. Included are pictures of various degrees of wear on critical parts such as bolts, operating slides, etc. You will find all the dimensions you have been asking about regarding the spring lengths too. I think it still sells for around $30. - Bob