Lapua 6BR flash holes

[AlNyhus]

I’d say if having to work on primer pockets a smidge is as large of an issue as we can come up with, Lapua still stands alone as the best there is.

Agreed! .

 

[C.E.Smith043]

Al, I appreciate the care that you take with your cases and understand that you compete.
When I first ordered my 6BR from Cooper a little over 20 years ago they tried to discourage me by saying brass availability could be problematic. So I just went out sourcing brass wherever it was available. I bought up 400 rounds of Lapua and also 400 Remington. People started to suggest opening up the flash holes. At that time, I was under the impression that all you needed for proper ignition was a spark and sufficient pressure for the powder to burn properly. I tried every primer and powder combo combined with Euber 68 gr. bullets and couldn't detect any difference on target with my rifle.
So my question is, can you see the difference real time on target with reaming flash holes?

Remington and Lapua continue to shoot the same groups although the Euber bullets are no more.
All groups are 5 shots

View attachment 1630440View attachment 1630442View attachment 1630443

If my memory serves me correctly, there was a study done that was published in PS magazine that stated the flash hole size did make a difference. Although, I don't remember the exact data, I do remember it being a factor in a more accurate load.

Also I feel like I remember someone was actually trying to develop a case that had a flash tube that ran upwards into the powder charge and would ignite the powder on the way up.

 

[ELR LVR]

And yet, I've been questioned regarding my opinion on consistent quality of Lapua brass
Isn't Lapua's flash holes suppose to be drilled?
At least that's what I was told years ago

 

[fkimble@charter.net]

Thanks Al. At least I got the "W" part right! I remember Ron H. name but can't associate anything with it? Old age at it's best/worst!

Frank

 

[JMayo]

I use a long pointy rcbs thing to debur flash hole when bringing on new cases. I've never seen much come from it. Just a light spin to verify all is well

 

[Mulligan]

And yet, I've been questioned regarding my opinion on consistent quality of Lapua brass
Isn't Lapua's flash holes suppose to be drilled?
At least that's what I was told years ago

I remember reading something from Lapua about this.
From what I recall, they tested drilling and punching flash holes and punching gave better results.
I am not sure how they defined "better"? I cannot find the source of my info????
CW
Edit
Maybe Phil can chime in on this?
@barefooter56

 

[AlNyhus]

Isn't Lapua's flash holes suppose to be drilled?

Lapua's flash holes are punched, not drilled. -Al

 

[WSnyder]

Thanks Al. At least I got the "W" part right! I remember Ron H. name but can't associate anything with it? Old age at it's best/worst!

Frank

Ron Hoehn: gunsmith, experimenter, BR parts and accessories supplier, tuner maker. Probably best known for his rimfire work.

 

[fkimble@charter.net]

Ron Hoehn: gunsmith, experimenter, BR parts and accessories supplier, tuner maker. Probably best known for his rimfire work.

Tks WSnyder!

 

[LCazador]

I've been seeing the discrepancies that you talk about with Lapua brass more and more. I'm no longer a fan. The last batch of Lapua 6BR brass I used was horrible. 9-10 discards out of 100 and yes you can square the bottom of the pocket be setting up a K&M tool for that dimension. Maybe that's why Les Bruno is endorsing Alpha brass now. I might add that there's also been quite a difference in rim thickness as well. Yes I sort that dimension as well.

 

[ASbobcat]

I've been seeing the discrepancies that you talk about with Lapua brass more and more. I'm no longer a fan. The last batch of Lapua 6BR brass I used was horrible. 9-10 discards out of 100 and yes you can square the bottom of the pocket be setting up a K&M tool for that dimension. Maybe that's why Les Bruno is endorsing Alpha brass now. I might add that there's also been quite a difference in rim thickness as well. Yes I sort that dimension as well.

Could you be more specific about the rim issues? Any problems fitting shellholders?

This sounds like a replay of the Norma Dasher fiasco a few years ago.

 

[Clancy]

Man…. Mine has been perfect as usual.

I hope you guys are letting the company know about this. I know they’d like to hear about it and confident they’d make it right.

 

[LCazador]

Could you be more specific about the rim issues? Any problems fitting shellholders?

This sounds like a replay of the Norma Dasher fiasco a few years ago.

Yes they won't fit shell holders. The other issue is the rims being curved or the extractor slots have burrs.

 

[ASbobcat]

Yes they won't fit shell holders. The other issue is the rims being curved or the extractor slots have burrs.

Thanks. Sounds like maybe outsourcing to catch up with demand. Notice that every supply house this side of the Atlantic can't give the stuff away at sale prices.

 

[JFrank]

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.

 

[fkimble@charter.net]

Glad to hear I'm not the only one having new brass being snug/too snug in the shell holder. First pass thru the shell holder with an expander to reduce tension it showed up. Slightly snug cases got a red sharpie stripe. Ones requiring more effort to go in shell holder got a complete red head! Red heads were always a problem! The full red head cases also caused extraction problems. Rim seemed to be too thick for the extractor to bolt face gap. If chambered slowly while paying close attention, you could fill the extractor not going over the rim edge.

Frank

 

[ASbobcat]

Glad to hear I'm not the only one having new brass being snug/too snug in the shell holder. First pass thru the shell holder with an expander to reduce tension it showed up. Slightly snug cases got a red sharpie stripe. Ones requiring more effort to go in shell holder got a complete red head! Red heads were always a problem! The full red head cases also caused extraction problems. Rim seemed to be too thick for the extractor to bolt face gap. If chambered slowly while paying close attention, you could fill the extractor not going over the rim edge.

Frank

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.

 

[Laurie]

If my memory serves me correctly, there was a study done that was published in PS magazine that stated the flash hole size did make a difference. Although, I don't remember the exact data, I do remember it being a factor in a more accurate load.

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.

 

[AlNyhus]

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.

Mine cleaned up nicely across the bottom at .123. I've not seen any as deep as yours...yet.

 

[fkimble@charter.net]

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