Lapua 6BR flash holes

[64Rambler]

Why 'funny'? As I said, Alpha has adopted the larger 2mm flash-hole in its larger case small primer brass - 308, Creedmoor, 6GT. Your readings are spot-on for this hole size.

It was funny to me because I had literally just checked with the pin gauges and this post was the first thing I read when I clicked on this forum for the day. Nothing funny about the info. I was checking the hole size to order drills for my Lapua brass as a comparison; before, after, compared to Alpha.

 

[AlNyhus]

Do you feel that the radius accross the bottom should be 'flattened'?

Absolutely. The radius is large enough that a primer can feel like it's bottomed out when in fact, the primer anvil is being held off the bottom of the pocket. Primers need to have the anvils 'loaded' for consistent ignition.

Hope this helps. -Al

 

[JLT]

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.

Elmer Keith did that many decades ago, borrowing the idea from cased artillery ammunition. He did that while working with his .338-.378 KT. Reading about it, it seemed like an awful lot of work, but he got what he was looking for. It promoted more complete combustion of large charges of slow burning powder. If I recall correctly, he was working with H870.

 

[barefooter56]

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

They are punched. If they would drill them the production speed would decrease greatly. Sinclair flash hole tool reamer was .0625. You have to realize also that decapping pins are cut from wire stock and their diameter can vary. The .0625 was picked so the the decapping pin diameter on the big end of the specification would have sufficient clearance and not " stick" in the flash hole.

 

[Mulligan]

They are punched. If they would drill them the production speed would decrease greatly. Sinclair flash hole tool reamer was .0625. You have to realize also that decapping pins are cut from wire stock and their diameter can vary. The .0625 was picked so the the decapping pin diameter on the big end of the specification would have sufficient clearance and not " stick" in the flash hole.

Awesome, thanks Phil.
CW

 

[barefooter56]

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

There are no SAAMI or CIP specifications for shellholders that I know of. The LAPUA brass has to be made to the European CIP specifications that can vary slightly from our SAAMI specs. At Sinclair we had customer calls about the cases not fitting in the shell holder. We took these concerns to REDDING and they modified their shell holders. And if the cases dont fit in a REDDING SHELLHOLDER you purchase they will machine you shell holder to work. Rim thickness can also cause this and extractor issues in some cases. Having the extractor claw widened and or made deeper is the fix here.
In regard to the "OUT SOURCING" speculation of the production of these cases is not true.
For my 6BR and 6.5X47 LAPUA cases I had to have the shell holders modified by REDDING so.. "been there done that"

 

[barefooter56]

I didn’t ever think I would have to purchase a small diameter flash hole tool for Lapua brass. I guess I had better get to looking, what brand to get guys?

SINCLAIR INTERNATIONAL SINCLAIR FLASHHOLE REAMER | Brownells

Check out SINCLAIR INTERNATIONAL SINCLAIR FLASHHOLE REAMER | Brownells available Online at Brownells Today and many more Primer Pocket & Flash Hole products are available in our Reloading Department.

www.brownells.com

 

[dat]

Absolutely. The radius is large enough that a primer can feel like it's bottomed out when in fact, the primer anvil is being held off the bottom of the pocket. Primers need to have the anvils 'loaded' for consistent ignition.

Hope this helps. -Al

Yes it does and thank you! Explains what I am feeling seating into 4 - 5 year old Lapua 6br brass. It has a radius. My primer depth tool just shines a ring on outside of the botom of the pocket. When seating primers, Rockchucker (I know, old style), I feel hitting bottom. Then with more pressure, I feel a bit more movement to a stop. This movement is probably the anvil being pushed to the bottom of the pocket in the radius.
Thinking, just cut enough on bottom of the pocket to privide a solid anchor for the anvil would be adequate, not necessarily cut all the way to the flash hole - say half way. Thoughts?

 

[ArtinNC]

I just got 100 Lapua 223 Match brass and they have large flash holes . And I though Lapua match had small flash holes . These flash holes are quite large.

 

[Bill Norris]

I just got 100 Lapua 223 Match brass and they have large flash holes . And I though Lapua match had small flash holes . These flash holes are quite large.

I believe all the .223 Lapua brass I have seen had large flash holes.

 

[Laurie]

I believe all the .223 Lapua brass I have seen had large flash holes.

Just so! I've never seen, or even heard of, a small flash-hole 223 case. Any that exist must have been specially commissioned as one-off batches. 223 uses the standard 2mm (0.78-inch) diameter hole.

Lapua renamed its 223 Rem brass as 'Match' some 15 or so years ago when it changed specs from its previous very heavy (>100gn), thick-walled / low-capacity 223 which had more in common with the heavier European 5.56 brass such as that produced by M.E.N. than with 223 used in F/TR and other match disciplines. Initially it didn't stamp 'Match' on the case-head stamp, only printed it on the (cardboard, gold colour) box.

 

[ArtinNC]

Just so! I've never seen, or even heard of, a small flash-hole 223 case. Any that exist must have been specially commissioned as one-off batches. 223 uses the standard 2mm (0.78-inch) diameter hole.

Lapua renamed its 223 Rem brass as 'Match' some 15 or so years ago when it changed specs from its previous very heavy (>100gn), thick-walled / low-capacity 223 which had more in common with the heavier European 5.56 brass such as that produced by M.E.N. than with 223 used in F/TR and other match disciplines. Initially it didn't stamp 'Match' on the case-head stamp, only printed it on the (cardboard, gold colour) box.

Mine says Match on the case head.

 

[Laurie]

Mine says Match on the case head.

Yes, as previously said, Lapua didn't initially put the word on the case-head. They did so after a few years., presumably to avoid confusion with any older lower capacity cases still around. (There is no 'non-match' version though, at least not on the commercial market.)

 

[snod85]

I got nervous reading this thread so I checked two new boxes of recently purchased 6br Lapua brass. Every single primer pocket and flash hole was perfect. Quit checking after two boxes. Did not gage the flash holes but the decapping die pin cleared on the 20 random pieces I tried. I did have dented case mouths on nine pieces of 200, two of which were fairly bad. All can be reworked easily.

I’ve been using Peterson and Alpha the last few years and their shipping boxes are better with individual slots so while I’ve had a few dinged pieces not to this level with the lapua loose box. I did not keep records so its just my recollection but the amount of dings is similar to other bulk brass I’ve bought in the past.

The ridge or burr on the case mouth was less pronounced than the Peterson and about the same as Alpha. All the Peterson I’ve tried has a noticeable ridge/lip around the mouth edge. Will still chamfer the Lapua before loading but it is good to go as is. The peterson I have is 6br, 284, and 6x47. The Alpha I have is 6gt and 308.

My recently purchased Lapua 6br brass looks really, really good, dings notwithstanding. If I decide to weigh cases and get some water capacity measurements I’ll post the results. If the weather is good I’ll probably just load and go.

Just fyi.