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Lapua 6BR flash holes

JFrank said:
Interesting to note that a K&M uniformer set at .123 would not touch the bottom of the pockets on all my Lapua 6 br brass. I had to switch to 21st century set at .126. Not sure what’s up with that but it seemed like an easy fix.
Hopefully I’m not alone.
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You're not alone. I've had to reset my uniformer several times. Trying to hold the case while doing this is another issue. I use a rubber tube on the case and gloves and it's still difficult. I'm using a different brand!
 
ASbobcat said:
Great information. What percentage would you say are usable?

This "smells" of NORMA outsourcing. Has anyone with an inside connection tried to find out if that's the situation? I recently returned a batch of Norma 223 brass because the necks were .014in. They were also heavy (100gr+) and had significantly reduced capacity. I have encountered many examples with other manufacturers trying to make up for softer brass by making it thicker.
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Not sure why the malleability of brass is an issue if dimensions are inline. I know that RWS is making brass for Norma and what I've seen lately in 222 and 22 Hornet is very consistent. I have yet to try some in 22/250 that I purchased recently but first look at consistent and accurate dimensions have my attention.
 
Kevin1990 said:
So I just read another thread about some issues with lapua 6br cases. I decided to look at mine more thoroughly. I inspected 100, and nearly all of them have burrs in the flash hole. A few I inspected had oblong flash holes too, so thats nice
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Kevin, I'm glad you took the time to check this. It's easy to correct and should be done as part of the prep process...no matter what the brand.

Hopefully the  other issue you posted about will be taken care of quickly, and to your satisfaction.

Good shootin' :) -Al
 
fkimble@charter.net said:
ASBobcat, I had about12ish that I marked. About 5 would not extract .Now this was all in the first 10-15 rounds fired. They all fired fine. They shot fine. I'm using them in a Stolle Atlas with the sliding plate extractor. While the rim is a hair thick, I think the slide may be the real problem. It slides in a channel and has no up/down play, just in and out. Only discovered the problem when for some unknown reason in the middle of a group, I decided to rechamber a just fired round? It went in easily but would no extract. No pressure opening bolt or pulling it back wards, just no case. It is a coned bolt model. I just reached in with a spring hook and hooked the rim and it came right out. These cases have been shot and fired a second time with no problems. Since they were new and a thousandth or so short on headspace, the rim may have reached the back end of chamber with no gap between end of barrel and rim for the plate to slide into the grove. My 3 month older box of brass has had no problems. Hope this helps.

Frank
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Frank, thanks for the additional information.

I guess a few per hundred is acceptable, if primer pockets hold up.

I have Savage actions, which also have a sliding plate extractor, so that is an issue for me.

Bob
 
LCazador said:
Not sure why the malleability of brass is an issue if dimensions are inline. I know that RWS is making brass for Norma and what I've seen lately in 222 and 22 Hornet is very consistent. I have yet to try some in 22/250 that I purchased recently but first look at consistent and accurate dimensions have my attention.
Click to expand...
You are a well respected member of this community, so I don't wish to sound disrespectful. But if you don't understand the relationship of brass malleability to primer pocket durability, you may wish to consider taking a course in metallurgy.
RWS making brass for Norma is a good thing. Norma making brass for others, maybe not so much.
 
ASbobcat said:
You are a well respected member of this community, so I don't wish to sound disrespectful. But if you don't understand the relationship of brass malleability to primer pocket durability, you may wish to consider taking a course in metallurgy.
RWS making brass for Norma is a good thing. Norma making brass for others, maybe not so much.
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Thanks and I understand what you're talking about. Maybe I don't take my brass to the extreme where pockets don't hold up. I had a primer pocket leak and ruin a bolt and trigger. Softer brass did not encourage that issue, it was high pressure! I never went there again and have not had an issue with that since.
 
I just wanted to hop back on here, and say that I do not have any oblong flash holes in my 6br lapua brass. I dont want to add to problems, especially if they don't exist. I was mistaken. After re-examining the ones that I thought were oblong, it was just the burr inside the flash hole. When looking at it certain ways that burr makes it look oblong. Need to get the K&M flash hole uniformer.
 
I went through this awhile back.
chkunz said:
How do you know it made a difference?
If I tried it and said that it did not make a difference, how would you know?
This is not an adversarial reply.
I appreciate your input to a subject that I have an interest in.
Best wishes
Clyde
Click to expand...
I segregated the unexplained flyers at 1300 yards. Borescope showed a burr inside those cases. It eliminated that issue. Lucky? Maybe. But they all get it now
 
Kevin1990 said:
I just wanted to hop back on here, and say that I do not have any oblong flash holes in my 6br lapua brass. I dont want to add to problems, especially if they don't exist. I was mistaken. After re-examining the ones that I thought were oblong, it was just the burr inside the flash hole. When looking at it certain ways that burr makes it look oblong. Need to get the K&M flash hole uniformer.
Click to expand...
Kevin, the K&M will make life a lot easier. :) -Al

P.S.- Hopefully that mess with your barrel has been handled to your satisfaction.
 
Laurie said:
Yes. It reported that if flash-holes are reamed to ~0.070" or larger on small precision numbers such as the 6BR and PPCs, groups and ES/SD values became larger.

More recently, on Creedmoor / 308 Win case sized cartridges, Alpha says that its tests have shown improved results with the standard 2mm / 0.079" flash-hole on their SP variants.

These two sets of findings aren't contradictory as it's long been understood that both the size and weight of the powder charge (even the brass case area) affect reliable and optimum ignition requirements. (Not to mention the powder grade/type, ambient temperatures and more.) The dividing line seems to be the 6.5X47 Lapua, the company making prototypes in both large and small versions and choosing the latter (with 1.5mm flash-hole diameter) as providing more consistent results.
Click to expand...
Funny, I just checked my Alpha 6BRA brass and an 080 pin fit snugly, 081 no go, 079 easy fit.
 
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