Need help choosing neck size, new barrel

[jdw91]

Hi all,

I'm looking to get a new (and my first) 6BR barrel and am a bit confused/worried about neck dimensions. I have a line on a new Shilen Select Match 6BR barrel 1:8 twist, .271 no turn neck (25.5" and .85 at muzzle). I've been doing a bit of reading and it seems that some would say that .271" is a bit tight. The last thing i want to do is worry about pressure while enjoying the new build, so what is the ultimatum? I'd really like to get this barrel and will be using lapua brass. If i got the barrel and found that the lapua brass is a tight fit, can i just turn it? What about neck sizing dies?

Any help would be greatly appreciated!

Jake

 

[Steve Blair]

Most folks call a .272 neck a no-turn. You are correct, .271 is a little tight. My reamer is .269 and requires a light truing cut. I size with a .265 bushing for Sierra 107s. When I shoot Lapua Scenars, they have just a little less tension and mike about .0005 smaller than the Sierras. The throat is .104 for 105-108 bullets.

If you find the particular lot of Lapua brass you buy is a little tight, take a .001 cut on the neck and it will be fine. You could also have a reliable gunsmith go back in with a piloted neck reamer and open to .272, but it makes me nervous to do anything after the initial chambering.

 

[philipmurphy]

How about asking Pacific to make you a chamber reamer for the brass that you intend to shoot, say Laupua or Norma? Now you're done. No neck turning.

Phil

 

[varminthunter1]

If I were doing a new build I`d start with a longer barrel. 28" -30"
The 6br is just plain magic, easy to load, 30+gr of Varget and a 105gr projectile = 2900fps and outstanding accuracy. I think the .271 nk is fine, I personally think neck turning is a critical key to accuracy, but to each there own.
You really cant stuff enough Varget in there to have pressure problems. make sure you have your smith chamber the gun with -.001 headspace, just to be sure its tight!(thats one thousandths of an inch smaller than the go gauge)
You should have a winner! good luck.
Jeff

 

[Ackman]

Measure your brass and see. My reamer has a .271" neck, loaded brass is .269". Works perfectly. Some have said their brass has a little thicker neck than that. If ever I get more and it's thicker, a light cut with the neckturner will change that. Neckturning isn't difficult. Best way is to get brass first, then spec your own reamer.

 

[sdneil]

Ackman is correct--loaded Lapua brass measures .269--.271 neck is perfect--and you can put to much Varget in a 6br case to have a pressure problem!