Very tight bore for 308Win?

[gunrunner8]

Recently I rechambered 308Win target barrel into high performance 30-06 RCBS Imp cartridge.
The only difficulty was that the bore size on that barrel was .297" instead reg .300" and I had to machine special bushings for reamers to even enter the bore.
What is behind that new (?) idea?
New standard? Better cast bullet performance? Longer lasting rifling? To sell more reamers? Any other reason?

 

[maynard]

Tight bores were used in the days of sloppy fitting issued ammo. I think the Kreiger barrel (soon to be replaced) that I have on now is a .298"x.307". Only because that is a barrel Krieger had on the shelf at the time, with no waiting period. And yes the pilot bushing for the range rod/reamer had to be machined down to fit. I can't say that this barrel was any better or worse than any other barrel I have used. All barrels only last about 3-3.5 seconds anyway

 

[coyote]

Some barrels are made with smaller bores maybe it was ordered like that? I make my 30 cal barrels with a .2999 reamer so after lapping it will be pretty handy to .300, Boots Obermeyer makes his with a .297 or .298 bore he told me last year that he likes to rifle extra deep.
Saami spec would be .300" but some custom makers offer different sizes so chances are this is what you ended up with .