When you look at the commercially available bolt action rifles prior to WWII, the pre 64 Winchester was the best.
Pre War M70’s also show the best workmanship, least tool marks on the metal.
The design is still an excellent design, it is slick and smooth. The original over ride trigger was the best of it type.
There are features I like on the pre 64’s that were lost in later revisions. The firing pins are easier to take apart, I like the milled feed lips in the receiver. I don’t like the cone breech and the fact that if you pierce a primer the gas is going straight down the firing pin shaft into your eye. I like the stripper clip slots on the pre War and NM receivers.
I believe Winchester ran their equipment into the ground manufacturing Garands and Carbines during WWII. Post WWII rifles show all the characteristics of worn out tooling and inefficient process control. Parts are not necessarily interchangeable, I see file marks on bolt parts. One gray beard, his first pre 64, fresh from the hardware store, would not feed.
I have heard that Winchester lost money on each and every M70 they sold. Winchester had to do something and they did, in 1963 they revamped the line. It was dishonest to keep the same model number for the revised action, but they did. Corporations are interested in maximizing profits, changing the name would lost all the advertizing value from previous decades.
M70 actions and Rem M700 actions were the most popular bolt actions used in Highpower Competition till Space guns and Tubb rifles displaced them. The M70 has a particularly smooth and slick action, parts hardly break, the receiver is very stiff and easy to bed. It was a great target action.
I am of the opinion that the FN manufactured M70’s are the smoothest and best built to date. Unfortunately the FN parts are not interchangeable with the pre and post 64 rifles. And they dropped off the original over ride trigger. They did improve the gas handling a bit by building g the bolt shroud wide enough to block gas coming down the left receiver side.
Post War Featherweight on top, Pre War on bottom.
Pre War, stripper clip slots
Post war, no stripper clip slots
PreWar, good machining and finish