30 cal bore diameter

[mshelton]

Getting ready to order a barrel for a long range hunting rifle for next fall, 300 Ackley based of the 375 H&H case.

Trying to decide on a bore diameter, I'm planning on shooting bullets in the 210 range (208 A-Max, 210 Berger or 210 LRAB depending on what shoots best) and I need to decide on bore diameter, I'm thinking .299/.307 to be just a tad snugger but wondering if there is any reason to go tighter. I know the Palma guys liked bores in the 298/306 range for various reasons but I'm thinking that's going to be too snug for what I want to do.

Any suggestions or light someone could shed on this for me would be appreciated.

 

[stgw77]

Pressure issues arise when using heavy, long bearing surface bullets in tight bore/tight groove configuration. Krieger suggest against using bullets heavier than 175 grain, and/or magnum pressure cartridges in any .30 tight caliber barrels due to the dangers of high pressure and the increased chance of copper fouling. I think there is no need to use tight bores using modern bullets (Berger, Hornady, custom...). Palma shooters used tight bores becouse military ammo used smaller than .308" bullets.

 

[LawrenceHanson]

"I don't really care for tight barrels. There is a simple philosophy I use in all my equipment selection and it is "Don't solve a problem you don't have." I can't identify a problem that a tight barrel would solve; therefore, I get standard dimensions and they work great."

Germán A. Salazar

http://riflemansjournal.blogspot.com/2012/01/equipment-30-caliber-barrel-specs.html

 

[BOBC]

"I don't really care for tight barrels. There is a simple philosophy I use in all my equipment selection and it is "Don't solve a problem you don't have." I can't identify a problem that a tight barrel would solve; therefore, I get standard dimensions and they work great."

Germán A. Salazar

http://riflemansjournal.blogspot.com/2012/01/equipment-30-caliber-barrel-specs.html

With slightly tight groove diameter barrels just use less powder and still get good MV and longer barrel life. I did this for the 35 years of shooting NRA High Power which is brutal on barrel life. I was getting about 1000 more accurate rounds out of my barrels than many of my fellow competitors. I believe then Lapua's 30 cal 170 and 185 gr bullets were available in .309 Dia. which was a help to worn standard bore and groove diameter barrels.

It seemed the more rounds I put through my barrels the better they shot. I kept count on the number of rounds I put through them and changed them at the appropriate number of rounds, even if they were still shooting well. Did not want to take the chance of them dying on me half way through a match.

 

[dkhunt14]

I like the not so tight barrels and believe they yield more velocity. The one tight Krieger that I had in a 6 Dasher ran 100 FPS slower and 2 less grains of Varget. In my 300 WSM's I use the bigger bore. In our game you need to change barrels at 1000 rounds or less or you won't win often. When you dump ten rounds down a barrel in 30 seconds it gets real hard on them. When the throats start to wear you start to lose accuracy. Matt

 

[ShootDots]

DK, have you tried setting the barrel back say 150-200K? I did that on my first Dasher and so far the accurate barrel life is still singing along. I don't think you would get THAT MUCH firecracking in less than 1000 rounds, only throat erosion. It could be that once you get to say 750 rounds, you could set it back 200K and extend the useful barrel life by maybe 500+ rounds?

 

[gsg5pk]

If you decided to go with heavy projectile, don't look at tight bore.

Standard .300/.308 would be suggested.

 

[dkhunt14]

When I cut them off and rechambered they don't last as long. I have done it but I like new barrels. I have had some come back and some didn't. I also had 2 that lost pieces of metal and didn't last 500 rounds. When you dump 7 sighters in 6 minutes, with most being in the last 2 minutes and 10 records down the barrel in 30 seconds it gets real hard on throats. Matt