According to the Serial # on my early M760 it must have been manufactured around 1954, I did not get it new until 1957. It has been accurate with H4831 & IMR4350 pushing 130 grain C-L, and 130 grain Hornaday bullets. It has also been good with 150 grain bullets. For some reason my rifle did not like 150 grain power points but my brother's early 760 liked them. Extraction is not as strong as my bolt action 270s, so I have to drop of a grain of powder with some bullets. Extraction is good with Hornaday, but I need to drop that grain with Nosler, and Sierra bullets.
Admittedly the accuracy has dropped off with the installation of a new Burris scope. The next time I get out to the range I am going to pull the scope off and check the screws in the base mount.
p.s. it is clear off copper.