6x47L vs 6BRDX/BRX/Dasher

[ASbobcat]

While playing with the 6x47 Lapua I discovered an "issue" that some may want to consider before trying it.
The problem is with the thickness of the parent case, especially in the shoulder area. I cut a case in half and compared it to a 6BR case. The x47 is MUCH thicker all over but the difference is particularly noticeable in the shoulder. The "issue" arises because this brass is so tough that it virtually lasts forever if treated kindly. Over time, I found this thicker shoulder brass flows into the neck. Added to the thickness increase and run-out during initial forming and chamber clearance becomes a potential problem.
Most of us don't mind "one and done" neck turning, but I found turning to be a constant maintenance item 6x47L. No such problem exist with the 6BR "IMP" series because the shoulder of virgin 6BR brass is not noticeably thicker than the neck and fire-forming thins it even further.

After a brief venture into the 6x47L, and considering the trouble/benefit consideration, I'm returning to the 6BRDX.

 

[Phil]

I wonder if a 40* shoulder would slow this down??????

 

[MarkS]

While playing with the 6x47 Lapua I discovered an "issue" that some may want to consider before trying it.
The problem is with the thickness of the parent case, especially in the shoulder area. I cut a case in half and compared it to a 6BR case. The x47 is MUCH thicker all over but the difference is particularly noticeable in the shoulder. The "issue" arises because this brass is so tough that it virtually lasts forever if treated kindly. Over time, I found this thicker shoulder brass flows into the neck. Added to the thickness increase and run-out during initial forming and chamber clearance becomes a potential problem.
Most of us don't mind "one and done" neck turning, but I found turning to be a constant maintenance item 6x47L. No such problem exist with the 6BR "IMP" series because the shoulder of virgin 6BR brass is not noticeably thicker than the neck and fire-forming thins it even further.

After a brief venture into the 6x47L, and considering the trouble/benefit consideration, I'm returning to the 6BRDX.

I know a few guys that built 6 X 47L when the 6.5 x 47l came out, all had problems getting it to shoot for 600 yds benchrest. all of them cut the chambers off and went back to 6BR IMP. I did that route with the 6XC, I went back to the 6BRX.

Mark Schronce

 

[dbduff]

Collecting parts for 6x47 build. This is the first I've heard of a brass issue being interpreted as an inherent accuracy issue for this specific cartridge. Are other 6/47 users finding this interpretation to make sense down range? I've heard that there were complaints getting this combination to work as desired, but didn't hear anyone pin pointing a significant flaw in brass,compromising what should be, at least on paper, (small primer, Lapua brass, 6mm bullet selection) a great combination, esspecialy given the performance of the parent 6.5/47 Lapua cartrige. If what is being presented as a significant issue, now wondering if new Lapua 6 Creed moor might make more sense, or more of the same? Beginning to look like a rabbit hole.
D

 

[Cool Tool]

While playing with the 6x47 Lapua I discovered an "issue" that some may want to consider before trying it.
The problem is with the thickness of the parent case, especially in the shoulder area. I cut a case in half and compared it to a 6BR case. The x47 is MUCH thicker all over but the difference is particularly noticeable in the shoulder. The "issue" arises because this brass is so tough that it virtually lasts forever if treated kindly. Over time, I found this thicker shoulder brass flows into the neck. Added to the thickness increase and run-out during initial forming and chamber clearance becomes a potential problem.
Most of us don't mind "one and done" neck turning, but I found turning to be a constant maintenance item 6x47L. No such problem exist with the 6BR "IMP" series because the shoulder of virgin 6BR brass is not noticeably thicker than the neck and fire-forming thins it even further.

After a brief venture into the 6x47L, and considering the trouble/benefit consideration, I'm returning to the 6BRDX.

I have not found any real issues with the parent case of 6.5 x47 lapua never ever cut one to compare to other brass but I have formed it shortened it had know issues with length growing to much. PS here are some examples these are 6.5 not 6mm but I have had the same with 6mm I like experimenting.

 

[ASbobcat]

I wonder if a 40* shoulder would slow this down??????

Theoretically yes, but I've never owned one.

 

[savagedasher]

I know a few guys that built 6 X 47L when the 6.5 x 47l came out, all had problems getting it to shoot for 600 yds benchrest. all of them cut the chambers off and went back to 6BR IMP. I did that route with the 6XC, I went back to the 6BRX.

Mark Schronce

I had two first and last. 3 months i tried ever bullet And powder combination .
I though it was the barrel .
Cut part of the chamber off and made it a dasher . The first 10 shot were better then the best I ever had from the barrel .
Larry

 

[ASbobcat]

Collecting parts for 6x47 build. This is the first I've heard of a brass issue being interpreted as an inherent accuracy issue for this specific cartridge. Are other 6/47 users finding this interpretation to make sense down range? I've heard that there were complaints getting this combination to work as desired, but didn't hear anyone pin pointing a significant flaw in brass,compromising what should be, at least on paper, (small primer, Lapua brass, 6mm bullet selection) a great combination, esspecialy given the performance of the parent 6.5/47 Lapua cartrige. If what is being presented as a significant issue, now wondering if new Lapua 6 Creed moor might make more sense, or more of the same? Beginning to look like a rabbit hole.
D

I didn't say it was an accuracy issue, only a maintenance issue that I didn't want to have to deal with. In theory, tight clearance between neck and chamber should be MORE accurate.
Here's the real problem. If you don't check case neck OD after loading, you could end up with no clearance and failure of the neck to release the bullet. I found this out the hard way, blowing an extractor into the next county and having to pound the bolt open with a hammer.
My point in this thread is to save someone else from the same fate, or worse.

 

[ASbobcat]

I have not found any real issues with the parent case of 6.5 x47 lapua never ever cut one to compare to other brass but I have formed it shortened it had know issues with length growing to much. PS here are some examples these are 6.5 not 6mm but I have had the same with 6mm I like experimenting.

Another way to look at the thickness difference is that a 6.5x47L case weighs about 40grains more than a BR case but only holds about 6 more grains of powder.

 

[dbduff]

Another way to look at the thickness difference is that a 6.5x47L case weighs about 40grains more than a BR case but only holds about 6 more grains of powder.

Now I get what you're saying. Brass continues to flow into neck of case with repeated firings, consequently,to avoid too much grip by neck on bullet and subsequent extractor issues the user needs to turn necks after x number of firings. I assume as you approached this bullet grip issue the chambering got harder with each subsequent firing. Have I got the jist of your concern?
D

 

[Phil]

Now I get what you're saying. Brass continues to flow into neck of case with repeated firings, consequently,to avoid too much grip by neck on bullet and subsequent extractor issues the user needs to turn necks after x number of firings. I assume as you approached this bullet grip issue the chambering got harder with each subsequent firing. Have I got the jist of your concern?
D

This is how i took it too, hence my question about putting an Ackley shoulder on it..........

 

[ASbobcat]

Now I get what you're saying. Brass continues to flow into neck of case with repeated firings, consequently,to avoid too much grip by neck on bullet and subsequent extractor issues the user needs to turn necks after x number of firings. I assume as you approached this bullet grip issue the chambering got harder with each subsequent firing. Have I got the jist of your concern?
D

Yes. That is exactly the point. You won't see this initially, but it will begin to show up somewhere between 10 and 20 firings.
Most of us seat bullets above the neck shoulder junction donut, so your first indication should be difficulty chambering, after verifying that there is adequate headspace clearance. If you don't start turning at this stage, the real problem occurs when the thickened brass reaches the bullet bearing surface. It is very important to measure OD here rather than at the case mouth.

 

[ASbobcat]

This is how i took it too, hence my question about putting an Ackley shoulder on it..........

That's why I have chosen the BRDX route. Doug Paschall told me he gets very good brass stability even with very warm loads. I prefer a longer neck vs the Dasher, and the performance difference between the two appears to be negligible.

 

[mikecr]

Once removed(with turning) donuts don't just show up, we put them there with sizing.
How were you sizing?
Were you seating into donuts?

 

[dbduff]

Yes. That is exactly the point. You won't see this initially, but it will begin to show up somewhere between 10 and 20 firings.
Most of us seat bullets above the neck shoulder junction donut, so your first indication should be difficulty chambering, after verifying that there is adequate headspace clearance. If you don't start turning at this stage, the real problem occurs when the thickened brass reaches the bullet bearing surface. It is very important to measure OD here rather than at the case mouth.

Thanks for confirmation regarding brass flow. How many reloads were you getting before primer pockets loosened? How hot were your loads? 20 reloads would be impressive to my way of thinking, especially if pockets stayed tight. Was accuracy you hoped for?
D

 

[ASbobcat]

Thanks for confirmation regarding brass flow. How many reloads were you getting before primer pockets loosened? How hot were your loads? 20 reloads would be impressive to my way of thinking, especially if pockets stayed tight. Was accuracy you hoped for?
D

I was loading at 3300fps with 105gr from a 30in bbl with RL17. Primer pockets still as new (.1710) after more than 20 firings. Similar to my experience with Lapua 6BR brass, even at "impressive" loads, the stuff just lasts forever. I have more than 100 firings on the same 50 pieces of "brown/gold" box 6BR at 2950fps (30in bbl, RL17) and no neck turning required. The case heads just keep getting stronger with each firing, as long as you don't exceed the elastic pressure limit.
Accuracy better than I can hold the gun, .3moa or better in both.

Another reason I'm returning to 6BRDX is efficiency. 6x47L or 6XC burn 20% more powder to get 7% more velocity. That's a bad trade-off in my book.

 

[ASbobcat]

Once removed(with turning) donuts don't just show up, we put them there with sizing.
How were you sizing?
Were you seating into donuts?

I FL resize with Redding bushing dies. I always try to seat with bearing surface above the donut, but the brass flow bit me before I figured out why I'd blown the extractor. It is important to measure the neck OD at the point where your seating depth places the base of the bearing surface.

Any time you resize brass that is significantly thicker in the shoulder than the neck you're eventually going to get a donut. With bushing dies it will be on the outside and with non-bushing it will be on the inside.

 

[dbduff]

I FL resize with Redding bushing dies. I always try to seat with bearing surface above the donut, but the brass flow bit me before I figured out why I'd blown the extractor. It is important to measure the neck OD at the point where your seating depth places the base of the bearing surface.

Any time you resize brass that is significantly thicker in the shoulder than the neck you're eventually going to get a donut. With bushing dies it will be on the outside and with non-bushing it will be on the inside.

Once again, most helpful information. Also want to look into BRDX and also input on an Ackley shoulder on 6x47 to reduce or minimize the brass flow you experienced.
D

 

[mikecr]

IMO, the problem is not from thicker shoulder brass. I shoot a tight neck 6.5wssm, with shoulders nearly twice your thickness, and donuts do not form. I won't ever have to re-turn necks with it, or any of my other cartridges. The difference: I don't ever FL size.
Sounds to me like brass rolling into necks from your particular body sizing (being a lot).
How often do you trim?

 

[ASbobcat]

IMO, the problem is not from thicker shoulder brass. I shoot a tight neck 6.5wssm, with shoulders nearly twice your thickness, and donuts do not form. I won't ever have to re-turn necks with it, or any of my other cartridges. The difference: I don't ever FL size.
Sounds to me like brass rolling into necks from your particular body sizing (being a lot).
How often do you trim?

I'm sure that neck sizing will slow this process down and perhaps you will never run into this issue if you shoot modest loads as well. I let my brass grow until it is within .005 of chamber length and then trim after ever firing to maintain that length. This minimizes space for a carbon ring to form, and longer necks are associated with better accuracy.