"Tight bore" vs STD or nominal.. issues??

[Gappa]

I have been looking at barrels for a 308 build to shoot lighter bullets and I am seeing there are .300/.308 and then there are .299/.300 so what is the deal with this? What should I buy or what issues can I be faced with. Common sense would say jamming a .30 cal bullet down a .299 hole might cause pressure problems.
any advice??

 

[Alex Wheeler]

I have no experiance with the .30 cal. But I do with the 6mm. You can get a .236 or .237 bore. I have both. I can find no difference at all, they both will shoot the same powder charge at similar velocities. Accuracy is excellent in both. When you think about it, .001'' tighter bore means each land is .0005'' taller. I say get either one and don't look back.

 

[Gappa]

well it would seem a tighter bore would give a better gas seal and conform to the rifling better but on the downside it would seem the bullet could get swaged or deformed as it passes thru the hole

 

[FroggyOne2]

A .299x.308 bbl is not really considered a "tight bore" bbl. Back in the day when palma shooters were required to shoot the ammo of the host country, there was I believe in the '95 matches, due to the girth of the bullet that was being provided (Radway Green I believe), that needed a tighter bore in order to get it to shoot. I think also the older SIE155 this applied as well. Back then the tight bore was a .298x.3075