Shoney: Sorry, I meant a search of our archives here at TFL, and restricted to "Art of the Rifle".
The gist of his comments were that he'd never bothered to "break in" a barrel. A barrel-maker of his acquaintance told Gale that he always recommended a break-in pereiod, as that put more wear on the barrel and he could sell more barrels and sooner than for any normal usage...
I never heard of "break-in" before I came to TFL. I've been shooting and loading for the '06 since the summer of 1950. My uncle and father started in on centerfires and reloading in the 1920s. They never mentioned it, and I've seen them shoot many five-shot groups inside an inch. My uncle's 1949-vintage Gebby-barrelled Varminter regularly shot 5-shot 1/2" groups.
Thirty years ago, I didn't bother with "break-in" on two pets--didn't know about it, as I said. Those rifles still shoot inside one MOA, just as they always have. Ergo, why bother?
Another datum: The pet '06 got two four-shot, 4" groups at 400 yards. Then I shot a ten-shot string reasonably rapidly--two called fliers and eight shots in some six inches. This was last year, sometime. Maybe you can see why I don't worry a lot about "break-in".
That said, I'm certainly in favor of keeping a rifle clean. But after "messing" with some forty or fifty centerfires (haven't really kept all that close a count), I figure just shoot and enjoy.
NOW: For those who worry about this sort of thing and want to disagree with me, I can only suggest, "Go for it!"
Art