Lapua 6 BR Norma flash hole Photos

[Dave Way]

Today I began case prep on a lot of 500 Lapua 6mm BR Norma cases. I know, that sounds like a lot of work, but I love it. Every so often I see a post on here about whether or not to de-burr Lapua brass so I decided to investigate a little. These new iPhones have pretty good cameras as well as the ability to crop the image, so I decided to see if I could take advantage of that.

I picked 10 random cases and photographed the inside of the case. 9 showed no discernible burr at all. One, the second photo, shows a very minute burr. I will attach the photos, it may take two posts to attach them all.

I will not be touching the flash holes on these cases and thought others might want to see the images.

Dave.

 

[Dave Way]

Photos 6-10

 

[Mike_Carter]

What primer do you prefer? I've been using Federal GM205M with 30 grains of Varget for 6BR and today at the range I was getting craters and several blown primers. This was with Lapua brass shooting Berger 105 VLD Hybrids, Berger 105 BT Target, and Hornady 108 ELD-M. Brass was used and brand new. I was running a chronograph on every shot (2890-2840 FPS) and writing down speeds and there appeared to be no correlation between slower or faster speeds with the blown primers. Curious as to what you prefer and or have any experience with what I mentioned.

 

[gunsandgunsmithing]

What primer do you prefer? I've been using Federal GM205M with 30 grains of Varget for 6BR and today at the range I was getting craters and several blown primers. This was with Lapua brass shooting Berger 105 VLD Hybrids, Berger 105 BT Target, and Hornady 108 ELD-M. Brass was used and brand new. I was running a chronograph on every shot (2890-2840 FPS) and writing down speeds and there appeared to be no correlation between slower or faster speeds with the blown primers. Curious as to what you prefer and or have any experience with what I mentioned.

Crater ed and or pierced primers are not a good indication of pressure. They are usually a result of poor fit between the firing pin and it's hole. Remingtons are almost a certainty to have this issue. Sometimes it can happen due to a weak fp spring.

Do a search on here for catered primers. It's been discussed many times and there is good info on the subject with a little searching.

 

[Mike_Carter]

It is a Stolle Panda action and I did have a couple of instances today where it would not cock the bolt. It's a used gun and today was the first time I disassembled it. Pretty nasty. So a good clean up and lube will probably solve the issue. I hope.
Thanks for the information. I'm new to the HP game and this forum is a great time saver.
Regards,
Mike

 

[Dave Way]

I'm afraid I probably won't be much help here. This brass will be for 6mm BRA's and I don't have any experience with a straight 6BR but the loads don't appear to be excessive from what I've read. I would be double checking everything, scale, powder charge, seating depth, diameter of loaded round versus chamber neck diameter etc. Also, you could look at the face of the case head for signs of pressure, measure the heads of the cases for excessive expansion and maybe check your firing pin fit in the bolt. Others on here probably have more ideas. Good luck-Dave.

 

[gunsandgunsmithing]

It is a Stolle Panda action and I did have a couple of instances today where it would not cock the bolt. It's a used gun and today was the first time I disassembled it. Pretty nasty. So a good clean up and lube will probably solve the issue. I hope.
Thanks for the information. I'm new to the HP game and this forum is a great time saver.
Regards,
Mike

It can happen and for whatever reason, varget and a 6br seems to be a common combination for it. I wish I knew why. I had a Teddy that did it with varget in a 6brx but not as a 30br, 30 major or 6ppc...all loaded to at least the same pressures and more.
I still think it's a pin fit issue but that powder/case combo somehow seems to exasperate the problem. Most people run cci 450s to reduce or sometimes eliminate it vs a softer primer. Hope this helps

 

[dkhunt14]

What primer do you prefer? I've been using Federal GM205M with 30 grains of Varget for 6BR and today at the range I was getting craters and several blown primers. This was with Lapua brass shooting Berger 105 VLD Hybrids, Berger 105 BT Target, and Hornady 108 ELD-M. Brass was used and brand new. I was running a chronograph on every shot (2890-2840 FPS) and writing down speeds and there appeared to be no correlation between slower or faster speeds with the blown primers. Curious as to what you prefer and or have any experience with what I mentioned.

FEDERAL 205 primers have a thin cup. They are easier to crater and blank then others. Matt

 

[HTSmith]

One of the reasons the CCI 450 is so popular in this application is that they hold up better. That said not all 6BR's will stand the "standard" 30 gr load. I have one that will only go to 29.8 with Sierra 107's

 

[Mike_Carter]

It can happen and for whatever reason, varget and a 6br seems to be a common combination for it. I wish I knew why. I had a Teddy that did it with varget in a 6brx but not as a 30br, 30 major or 6ppc...all loaded to at least the same pressures and more.
I still think it's a pin fit issue but that powder/case combo somehow seems to exasperate the problem. Most people run cci 450s to reduce or sometimes eliminate it vs a softer primer. Hope this helps

As an update to this thread I wanted to let you know what my results have been since. 60 shots with the same load (30 grains of Varget) divided between new Lapua and once fired Lapua brass, half with CCI 450 and Federal GM205M. No significant primer cup deviation or blown primers with any combination. The biggest help, I believe, was a total disassembly of the bolt and cleaning and lubrication. It was filthy. Also, there was a pretty significant carbon ring in the free bore area of the chamber just before the lands. So this may have been creating a higher pressure.
I know this didn't really relate to the original thread topic but I wanted to at least give an update. Thanks for all the suggestions.
Mike