6BRDX vs 6BRAI
- Thread starter BradY
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Phil
Gold $$ Contributor
The BRDX moves the shoulder forward on the case during fire forming to add a little capacity.
I believe it moves .039" up the neck while adding the 40* shoulder.
The BRA forms by adding the 40* shoulder on fire forming while keeping the shoulder in essentially the same place as the 6BR...IE. no false shoulder / jamming the bullet necessary.
I believe it moves .039" up the neck while adding the 40* shoulder.
The BRA forms by adding the 40* shoulder on fire forming while keeping the shoulder in essentially the same place as the 6BR...IE. no false shoulder / jamming the bullet necessary.
DJSBRS
Site $$ Sponsor
Have your smith set the standard BR brass up for around 1 to 2 thou crush fit in the BRA chamber and brass comes out very uniform..I ff 200 pieces of brass this way and everyone was a keeper, didn’t have that with the Dasher,never ff BRDX though.
Cheers Rushty
I believe that Alex has said he chamber 0.004 short from a 6BR go-gauge, not from brass. Mine was chambered ~0.003 short of a go-gauge and I wouldn't have minded going to 0.004. With recent manufacture Blue Box 6BR Lapua I had some cases that were a touch loose on bolt close, most were okay but the extra thou would have been perfect.
Interesting. I couldn't get my head wrapped around why everyone was going .003 to .004 short of a standard BR go gauge. Is it the variance in brass length from the base to shoulder from Lapua?
Or is this just a typical practice for improved cartidges?
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tclaunch
Silver $$ Contributor
Not that I have seen.
Alex Wheeler
Site $$ Sponsor
.004 is standard and works very well. Some brass lots will give almost no feel on the bolt, some will be too tight. You should bump the shoulders if your cases feel too tight. I have at over 50 6BRA barrel/rifles out there and so far so good. My chamber depth tolerance is +/- .0005".
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Your thoughts on those cases that have little/no resistance on bolt close? I jammed bullets out of an abundance of caution. Would you say just fire them as is, knowing the headspace is basically within 0.001?
Alex Wheeler
Site $$ Sponsor
There is some variation in brass. The .004" seems to usually give a .002" crush. If you have little to no feeling on the bolt your still fine, jam or jump, up to you. Your probably at about zero, witch is fine. Remember that the only part of the case "headspacing" is a ring just around the neck, its not the same as a tight case with a formed shoulder, theres a lot more give here.
TZaun
Gold $$ Contributor
Alex, If you turn your necks and cut into the shoulder, does that take away that crush? Or am I thinking about it all wrong?
thekriebles
Gold $$ Contributor
Alex Wheeler
Site $$ Sponsor
I could see that happening if you cut deep enough.
tclaunch
Silver $$ Contributor
This isn`t a P.O. Ackley wildcat.....
This isn`t a P.O. Ackley wildcat.....
You called it, nothing to do with him ....... Jim
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