6BRA Alpha Brass question
- Thread starter savageshooter86
- Start date
Mine were that short straight out of the box before doing any prep work
Your lucky I'm happy for you.
I bought a box of dasher for the wife's dasher, used it for barrel break in. Then trashed it.
25 caliber
PA Jeep
Gold $$ Contributor
I wonder what die works with an Alpha reamer chamber? I see Alpha markets the Micron die from Bullet Central on their website. I understand Bullet Central used a Wheeler chamber design for the die dimensions. I wonder if the Alpha marketed Micron die reflects Alpha brass/chamber design??
Don't have any help for the 6BRA alpha brass ...but it fits perfectly in my 6 dasher. I purchased my own reamer and chambered it .272" neck, no turn.
The loaded round runs .2695" with a little variance.
And a .267" bushing all work together...as just right. Don't have any issues with heavy bolt lift, or brass through the first 400 pcs. Primer pockets were a little tight...solved with Remington 71/2 primer. I have run these cases hard, to see what was possible with different powders. Accuracy is pretty standard Varget and RL15...RL 15 the slight edge. Velocity is 6.5 Stabal 107 gr SMK 3132 fps.
110 SMK 3085 fps, 115 DTAC 3020 fps. The Alpha brass handled it all with no pressure signs or hard bolt lift...bolt lift was normal and easy.
Unless something is different with the 6 BRA brass it's strange to hear about all the problems.
This won't help you with problems Alpha is doing something right with respect to the 6 Dasher brass...at least the 400 I purchased. Just my experience with it so far....Will see what the future brings, brass problem, chambering problem, a miss match. A chamber cast of the rifles chamber may be in order, to compare with the brass you have.
The loaded round runs .2695" with a little variance.
And a .267" bushing all work together...as just right. Don't have any issues with heavy bolt lift, or brass through the first 400 pcs. Primer pockets were a little tight...solved with Remington 71/2 primer. I have run these cases hard, to see what was possible with different powders. Accuracy is pretty standard Varget and RL15...RL 15 the slight edge. Velocity is 6.5 Stabal 107 gr SMK 3132 fps.
110 SMK 3085 fps, 115 DTAC 3020 fps. The Alpha brass handled it all with no pressure signs or hard bolt lift...bolt lift was normal and easy.
Unless something is different with the 6 BRA brass it's strange to hear about all the problems.
This won't help you with problems Alpha is doing something right with respect to the 6 Dasher brass...at least the 400 I purchased. Just my experience with it so far....Will see what the future brings, brass problem, chambering problem, a miss match. A chamber cast of the rifles chamber may be in order, to compare with the brass you have.
Keefe300
Gold $$ Contributor
Alex alluded to the issue with his response after he talked with Alpha.
The issue as I understand it has to do with the 200 line. The Wheeler BRA reamer has a 200 line diameter of 0.4714. JGS reamers are +0.0005. So in theory you could have a reamer that measures 0.4719 at the 200 line. You then stack another half to full thousandth of an inch after chambering due to cutting fluid and polishing and you could have a 200 line that could be 0.4729.
Alpha has stated that 0.471 at the 200 line is max. So with their (Alpha’s) OCD head brass once your chamber is over 0.471 at the 200 line the brass will not expand enough to grip the chamber at the base of the case. This is what is causing the case to thrust against the bolt.
With the Dasher I believe the 200 line on the reamer print is 0.4707. So with the explanation above this will end up being closer to the stated by Alpha max of 0.471. That may be why people are having positive results with the Dasher and not experiencing the same issues as described by BRA users.
Hopefully this helps make sense of what is happening and why.
The only way I see to correct the issue if you want to use Alpha brass is to have a reamer ground with smaller measurements. But if you choose to do this you will also need a new sizing die to support your new measurement.
The issue as I understand it has to do with the 200 line. The Wheeler BRA reamer has a 200 line diameter of 0.4714. JGS reamers are +0.0005. So in theory you could have a reamer that measures 0.4719 at the 200 line. You then stack another half to full thousandth of an inch after chambering due to cutting fluid and polishing and you could have a 200 line that could be 0.4729.
Alpha has stated that 0.471 at the 200 line is max. So with their (Alpha’s) OCD head brass once your chamber is over 0.471 at the 200 line the brass will not expand enough to grip the chamber at the base of the case. This is what is causing the case to thrust against the bolt.
With the Dasher I believe the 200 line on the reamer print is 0.4707. So with the explanation above this will end up being closer to the stated by Alpha max of 0.471. That may be why people are having positive results with the Dasher and not experiencing the same issues as described by BRA users.
Hopefully this helps make sense of what is happening and why.
The only way I see to correct the issue if you want to use Alpha brass is to have a reamer ground with smaller measurements. But if you choose to do this you will also need a new sizing die to support your new measurement.
If you want to run Alpha you will want less at the .200 line so the cases can grip.
This CIP link is what the 6BRA cartridge/chamber was based off.
I am curious, based on first hand experience, what the .200 line diameters were on reamers that produced clickers when using non-Alpha brand brass in a BR or BRA chamber, and what was the minimum diameter number necessary to eliminate such?
Sad have 300 neck turned for gun. Never again
Alex Wheeler
Site $$ Sponsor
I'm going to say one last thing on this topic and Im done. I was involved in the preproduction testing. We were sent brass. It WAS based on my chamber. I was there. The Alpha guys were very interested in making the best stuff. Now when problems came up I heard many possible causes. I have only heard it was based on the cip chamber recently. Now, at the time of this brass coming out, there was no cip BRA chamber. Anyhow, tightening up the base may just be the way to make this brass work. But if it was originally not supposed to work in the BRA chambers we all had when the brass was designed, it was a big secret from all of us. And now its my chambers fault?
Ccrider
Gold $$ Contributor
Obviously it’s not your fault or a problem with your well proven chamber. The first batch of brass worked for you and everyone else that bought and used it based on your recommendation.
They changed the brass and did not tell you or anyone. Short and simple. This problem should have been made public as soon as it was discovered. It would have saved a bunch of us time, money and aggravation.
Link
Silver $$ Contributor
I had both of my 6BRA s rechambered to 6BR. Not in the know ;[
Tpb10505
Gold $$ Contributor
I just read through the entire thread and I think I may be having some similar problems as others? I didn’t check the base to shoulder measurement on the new Alpha OCD brass (what is it supposed to be?), but the new brass is difficult to close the bolt on (Alpha reamer w/ .120 FB done by a great ‘smith). I chose a starting load of 30.5gr N150 (w/ Berger 108’s) b/c I have quite a bit of it and have read positive things from guys using 150. Straight away I was getting ejector swipes at 2850-2870fps. Also after a handful of rounds I start seeing lots of tiny brass particles in the chamber and on my bolt.
On the 1x fired stuff I bump the shoulders a thou and they chamber much easier (Micron die), like any other round. Velocity topped out around 2950 with 31.4g N150 (heavy bolt lift, swipes of course). Settled on 30.8 which gave me about 3/8” elevation at 200yd, but it’s only running 2900fps. I haven’t shot enough of the sized brass to know if I’ll still get the brass flakes in the chamber, but I assume the swipes at the lower velocities are from the brass being too hard/undersized at the .200 line and not grabbing the chamber? Not sure why it’s so hard to close the bolt on out of the box when using Alpha’s own reamer (brass prep for virgin stuff is mandrel the neck, trim/chamfer/debur). Anyways, appreciate all the input and info everyone has already posted.
On the 1x fired stuff I bump the shoulders a thou and they chamber much easier (Micron die), like any other round. Velocity topped out around 2950 with 31.4g N150 (heavy bolt lift, swipes of course). Settled on 30.8 which gave me about 3/8” elevation at 200yd, but it’s only running 2900fps. I haven’t shot enough of the sized brass to know if I’ll still get the brass flakes in the chamber, but I assume the swipes at the lower velocities are from the brass being too hard/undersized at the .200 line and not grabbing the chamber? Not sure why it’s so hard to close the bolt on out of the box when using Alpha’s own reamer (brass prep for virgin stuff is mandrel the neck, trim/chamfer/debur). Anyways, appreciate all the input and info everyone has already posted.
PA Jeep
Gold $$ Contributor
So you are using Alpha OCD brass in a rifle chambered with the Alpha reamer and using a Micron Die.
You have heavy bolt lift / clickers when opening your bolt?
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Tpb10505
Gold $$ Contributor
On the virgin brass I have a hard time closing the bolt compared to stuff that’s 1x fired and sized. Bolt lift is heavy on anything past 2900fps with the new brass as well
Edit: what are clickers? I’ve seen that mentioned a bunch but am not familiar
USMCDOC
Silver $$ Contributor
i just picked up a 6BRA, the Alpha brass that the fella gave me some of the fired brass had pierced primers in them.. some flow to the ejector.. measured at the web .469. I think that there is six cases like that.. bothers me that after the first one he didn't stop and shot the others anyway.. geezleweez!
Necks on fired brass brass was at .271. There were a few that were primed but not shot, virgin.. neck unturned.. measured at the web was .466. and necks are at .266
The sizing die is a Harrell's, marked 2.5, set the die to bump the shoulder back .0025, but the shell holder was not touching the bottom of the die.. if it did, it pushed the shoulder back 10K. There was some fired brass in the bunch that only measured .467 at the web and the necks were sized to .2655.
The brass that was sized and had the .467 web stayed there at that number and the bolt on the action closed without issue..
The brass with pierced primers.. web stretched .003 is trash and will go in the brass bin.
Necks on fired brass brass was at .271. There were a few that were primed but not shot, virgin.. neck unturned.. measured at the web was .466. and necks are at .266
The sizing die is a Harrell's, marked 2.5, set the die to bump the shoulder back .0025, but the shell holder was not touching the bottom of the die.. if it did, it pushed the shoulder back 10K. There was some fired brass in the bunch that only measured .467 at the web and the necks were sized to .2655.
The brass that was sized and had the .467 web stayed there at that number and the bolt on the action closed without issue..
The brass with pierced primers.. web stretched .003 is trash and will go in the brass bin.
Same thing they r telling me right now wat did you ever figure out
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