so far i have only gotten this from remington, but i am still waiting for more info.
Answer
The 40X differs from the 700 in the fact that all the parts have been blueprinted, the barrel is a button rifled, hand-lapped, air-gauged match barrel. An airgauged barrel has had the bore diameter checked by inserting an appropriately sized probe into the bore to measure the inside diameter. The probe is connected to an air operated gauge that can measure to within a half of a thousandths of an inch.
The trigger is an adjustable match trigger that goes down to a 1 1/2 pound trigger pull.
Every 40X is targeted from the shoulder to assure accuracy.