6 mm BR question
- Thread starter ARshuter
- Start date
Way back when Rem BR had a case length of 1.520 and then Normal came along and standardized at 1.560. That way cases would not interchange. Few other small differences that escape me. Hope this helps.
Paul
www.boltfluting.com
Paul
www.boltfluting.com
lawman29
Gold $$ Contributor
The 6BR Norma and Lapua brass are the same (The Lapua brass is head stamped 6BR norma). http://www.accurateshooter.com/cartridge-guides/6mmbr/
Last edited:
SteveOak
Gold $$ Contributor
I have attached the C.I.P. (the Euro version of SAMMI, neither are listed with SAMMI) drawings for the Remington and Norma versions of the 6 BR.
The case length, L3, is the same for both. The significant difference is the OAL, 55.88 vs 62.00 mm for the Remington and Norma respectively. This was Normas' innovation to permit the use of longer bullets.
There are some tiny dimensional differences in the head dimensions. With respect to ballistic performance, they are the same and if you load you own, the cases are functionally interchangeable.
The case length, L3, is the same for both. The significant difference is the OAL, 55.88 vs 62.00 mm for the Remington and Norma respectively. This was Normas' innovation to permit the use of longer bullets.
There are some tiny dimensional differences in the head dimensions. With respect to ballistic performance, they are the same and if you load you own, the cases are functionally interchangeable.
That's correct. My first 6BR was chambered with a reamer that had the Rem lower body dia. and around half of Lapua cases were a slight interference fit. They'd chamber, but I took to carrying a soft-face mallet with me to get the bolt open to extract the tight examples. (Doesn't inspire confidence in your partner or the RO as people assume you're running way over-pressure!)
SteveOak
Gold $$ Contributor
The C.I.P. drawings are attached. R1, which is the maximum body diameter, is the same, 12.04 mm for both cartridges.
Please specify the dimension of the Rem "lower body diameter" that you see as different from the Norma on the drawing.
The rim on the Norma, "Case Head" dimension f, is .04 mm thicker. Hardly anything to get excited about and the chamfer angle of the case is 45 degrees vs 35 degrees. The other dimensional differences are in the "Junction Cone" and "Commencement of Rifling" which reflect the purpose of the Norma changes, to accommodate longer bullets.
Irrespective of what CIP shows now, chambers for the BR Rem based on reformed UBBR brass and later Remington manufactured factory brass were 'tighter' than those produced by all of today's off the shelf reamers.
The difference is stated in the 6mm BR cartridge guide on this forum (and as this was originally www.6mmmBR.com, there does tend to be a bit of experience and expertise around on it here). The subject has been done to death in tens if not scores of threads over the years, and the last time it arose, some people started to get a bit impatient with the 'chamber difference deniers'. Here is one of these many, many threads on Accurate Shooter on the issue. If you do a search, you'll find others although most discussions will now have been archived as the issue rarely arises nowadays.
http://forum.accurateshooter.com/threads/6mmbr-history.2250267/#post-21466490
Now frankly, I don't give a tinker's cuss over this matter one way or another as it's an historical issue and should only arise should the gunsmith have an old reamer. As I've never seen Remington 6BR brass in the UK in a couple of decades of using the cartridge (and it's been a long time since shipping companies whether internal or overseas will accept pre-primed brass anyway without various restrictions and big charge hikes) the issue for me was what matches 6mm BR Norma cases made by Lapua - and my chamber didn't.
In my case, it was an old spec pre-BR Norma reamer and I was told plainly and simply on this forum that no gunsmith who knows the cartridge should be using such, and that I should therefore take it back and demand that it (the chamber) be sorted. As it turned out, I found that the Redding 6mm BR 'small base' body die reduced the lower case body enough to give a snug and problem free fit in my rifle's chamber, and the rifle performed very well indeed. I would resize all new brass in the die before the first loading, and it would gradually expand again over the firings so that the odd tight example would reappear after four or five firings, so I'd routinely use the die every three loadings / firings.
The difference is stated in the 6mm BR cartridge guide on this forum (and as this was originally www.6mmmBR.com, there does tend to be a bit of experience and expertise around on it here). The subject has been done to death in tens if not scores of threads over the years, and the last time it arose, some people started to get a bit impatient with the 'chamber difference deniers'. Here is one of these many, many threads on Accurate Shooter on the issue. If you do a search, you'll find others although most discussions will now have been archived as the issue rarely arises nowadays.
http://forum.accurateshooter.com/threads/6mmbr-history.2250267/#post-21466490
Now frankly, I don't give a tinker's cuss over this matter one way or another as it's an historical issue and should only arise should the gunsmith have an old reamer. As I've never seen Remington 6BR brass in the UK in a couple of decades of using the cartridge (and it's been a long time since shipping companies whether internal or overseas will accept pre-primed brass anyway without various restrictions and big charge hikes) the issue for me was what matches 6mm BR Norma cases made by Lapua - and my chamber didn't.
In my case, it was an old spec pre-BR Norma reamer and I was told plainly and simply on this forum that no gunsmith who knows the cartridge should be using such, and that I should therefore take it back and demand that it (the chamber) be sorted. As it turned out, I found that the Redding 6mm BR 'small base' body die reduced the lower case body enough to give a snug and problem free fit in my rifle's chamber, and the rifle performed very well indeed. I would resize all new brass in the die before the first loading, and it would gradually expand again over the firings so that the odd tight example would reappear after four or five firings, so I'd routinely use the die every three loadings / firings.
what is IS...is that a middle eastern bunch-0-truble makers,,,,???,,,,Like Laurie said the "old" stuff is much different ,,,,it is ~.003" smaller at the .200 line,,,and smaller at the shoulder,,,,the "old" dies (like I have in cosmolene now and hope to never need em again,,) ,,,,will over size the new stuff and anything that is shot in a "new" modern Lapua/Norma chamber,,,,most folks have never even seen the old original stuff,,,,we used to have to form them from .308 basic brass that was made specificly to become 22 BR and then later the 6mm BR came to be ,,,...there was also the original (depending on whose reamer was used--this stuff was mostly cutom ),,,the chamber length was around 1.520" +/- a lil',,,,then Remington lengthen them to 1.560 to match the Norma stuff that came over from Europe first,,,,it was soft as butter (like the "new" Norma Dasher stuff is,,unless I am wrong )...then Lapua (which nobody on this side of the pond had even heard of ),,,came over along with 220 Russian Lapua that was necessary for PPC to be fully utilized ,,,,Roger
Here's a thought, Is Rem. BR brass still available ?? I haven't seen any listed for sale other than from a few private sellers
so if Rem BR brass is not available like both Lapua & Norma BR brass are, wouldn't that settle the question ??
so if Rem BR brass is not available like both Lapua & Norma BR brass are, wouldn't that settle the question ??
Had the same thing happen to me with a used Rem. 700. Took a Norma 6BR reamer and hand turned until it came to the shoulder. No more click or hard extraction.
It doesn't matter how old, it was a problem then and still will be. If you want problems chamber with the old Rem reamer. First the Lapua brass is superior to the REM STUFF. I would not even think of using the old Rem brass. That alone is enough to discourage using it. These guys figured it out years ago after building one. Matt
You are on point Roger.
I wish 6BR-Remington data would cease to be published all the way around, to help put a end to the confusion. I know of no one chambered in 6BR Remington any more, but literally 100's of people with 6mmBR Norma. It's like a prehistoric dinosaur!.!.!
Donovan's post is right on, Nosler's current website lists only 6BR Remington
http://load-data.nosler.com/load-data/6mm-br-remington/
Donovan's post is right on, Nosler's current website lists only 6BR Remington
http://load-data.nosler.com/load-data/6mm-br-remington/
http://www.grizzly.com/products/6mm-BR-Lapua-Chambering-Finish-Reamer/T10177
http://www.grizzly.com/products/6mm-BR-Chambering-Finish-Reamer/T23214?utm_campaign=zPage
What's the difference between these two? I know free bore and neck but other than that?
http://www.grizzly.com/products/6mm-BR-Chambering-Finish-Reamer/T23214?utm_campaign=zPage
What's the difference between these two? I know free bore and neck but other than that?
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