6mm BR sizing issue

boxhitch said:
first thought, without asking a dozen questions, is that your brass is tired
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"tired" brass isn't really a thing and even if it was, it does not thin out the neck wall.


jimbo14 said:
Do you anneal your brass?
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TOTALLY IRRELEVANT to the OP's problem.

Unannealed brass will cause more neck tension and inconsistent neck tension as the brass gets harder. It can also result in split necks. It CAN NEVER result in thinned out neck wall.


BigBraz15 said:
I am 99% sure it does.
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You need to be 100% sure that it does. There is a difference between a sizing bushing and a retaining collar for the decapping pin even though they kinda look similar.

Are you using a bushing die? If not then the problem is in the neck wall thickness or bullet diameter.


BigBraz15 said:
I will check it out, but confused why some brass holds bullets and others don’t.
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Either you didn't size some cases or the neck walls are thin or you have the wrong diameter bullets. There are limited possibilities here.
 
BigBraz15 said:
On the barrel is it stamped .272 neck, and my research back before I picked it up means I can use factory brass without turning necks. Does that sound correct?
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Measure the neck OD of a loaded case and you will find out. 🤷‍♂️

It is all basic junior school math:

.272" neck - .243" bullet diameter
= .029" / 2 because the case neck surrounds the bullet on two sides
= .0145"

If your case necks are thicker than about .013" then you are dancing with the devil.

If the neck OD of a loaded round is too tight in the chamber neck then you run the risk of massive overpressure when the case neck can't expand to let go of the bullet.

Then of course you could have spent 2 seconds and googled the question, which would have produced the following answer:

A standard 6mm BR (6BR) no-turn chamber typically features a neck diameter of 0.272 inches. Factory-loaded Lapua brass loaded with standard bullets (like 105 gr) yields a loaded neck outside diameter (OD) of roughly 0.267 to 0.270 inches
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I would wonder about the actual measured bullet diameter first. Other than that I would suspect that you may have not resized those cases.. maybe got thrown in with the resized ones buy accident.. sometimes it's something simple that happened.. Cheers
Edit: after reading further I think 257Wby is on the right track too. Just use your calipers on the inside and outside of a good case, write down your data then do the same on a loose case and compare the wall thickness. It's got to be something along these lines.
If your using a bushing type die, it's probably related to that.
 
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270WSMXBolt said:
I would wonder about the actual measured bullet diameter first. Other than that I would suspect that you may have not resized those cases.. maybe got thrown in with the resized ones buy accident.. sometimes it's something simple that happened.. Cheers
Edit: after reading further I think 257Wby is on the right track too. Just use your calipers on the inside and outside of a good case, write down your data then do the same on a loose case and compare the wall thickness. It's got to be something along these lines.
If your using a bushing type die, it's probably related to that.
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Thanks for this. I will pull my die apart and measure.
 
I Dont Care About You said:
"tired" brass isn't really a thing and even if it was, it does not thin out the neck wall.



TOTALLY IRRELEVANT to the OP's problem.

Unannealed brass will cause more neck tension and inconsistent neck tension as the brass gets harder. It can also result in split necks. It CAN NEVER result in thinned out neck wall.



You need to be 100% sure that it does. There is a difference between a sizing bushing and a retaining collar for the decapping pin even though they kinda look similar.

Are you using a bushing die? If not then the problem is in the neck wall thickness or bullet diameter.



Either you didn't size some cases or the neck walls are thin or you have the wrong diameter bullets. There are limited possibilities here.
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Thank you. I will pull my die apart and measure. It is not a bushing die currently, it is a full length die.

All bullets are sized, none of them got missed, I have a very thorough process, and a bit confused by all of this. After almost 30 years of loading I have never saw this. The ELDX definitely does seem to be more loose, so perhaps slightly smaller in diameter than the Lapua’s. I will measure some this afternoon and post back results.
 
I Dont Care About You said:
The amount of stupid in this thread is just SHOCKING.

All the people advocating to push the shoulder back, please explain how the headspace relates to the neck dimension ........... I'll wait.
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I was pondering on this one today, and it isn’t clicking how bumping the shoulder will change the diameter of the neck. Am I missing anything here?
 
So I am measuring things here.

Hornady ELDX 103 grain 0.243”
Lapua Scenario-L 90 grain 0.2435”

Outside neck of resized case that is loose on ELDX 0.269”

Outside neck of case that will hold ELDX 0.2675”
 
BigBraz15 said:
I was pondering on this one today, and it isn’t clicking how bumping the shoulder will change the diameter of the neck. Am I missing anything here?
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Your not missing something. Neck sizing is different than shoulder bumping. If your using a full length non bushing type die and the bullet diameter is correct.. the only thing it can be is the wall thickness of the necks. In that case you will need a bushing type die with the appropriate bushing for that wall thickness. Cheers
 
Take the outside measurement of a case then subtract the inside measurement then do the same for a the different case and compare the wall thickness.
 
Your starting to get it and are moving forward on the right track. The rifle, bullet type and case types is complicating the process but it's all doable if you just think it through. You should add a few new tools to your kit to make things easier. I would stop using the expander ball in the die and use a separate expander mandrel for your processes. Neck wall thickness gauge and maybe "21st Century" expander mandrels for the different bullet diameters. Though I don't load that cartridge I can see exactly what your dealing with now. Welcome to next level reloading and the world of consistent neck tension. Utoobe is your friend here. Cheers
 
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boxhitch said:
but it does effect the elasticity and the return-to-shape, stiff tired brass doesn't respond as well as fresh or annealed, the reason such things are done
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Exactly.

With limited info that reads like the OP was new to reloading and now some bullets are loose in some brass (mix of old and new), my first thought was annealing, not thin walled brass.

Glad the OP found out what he has. It’s easy from here.

OP: I use both .267 and .266 in my 6BR and 6GT. Cannot remember what I’m using in my 6BR with Lapua brass. One of those. 🫣 Probably .267.
 
jimbo14 said:
Exactly.

With limited info that reads like the OP was new to reloading and now some bullets are loose in some brass (mix of old and new), my first thought was annealing, not thin walled brass.

Glad the OP found out what he has. It’s easy from here.

OP: I use both .267 and .266 in my 6BR and 6GT. Cannot remember what I’m using in my 6BR with Lapua brass. One of those. 🫣 Probably .267.
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jimbo14 said:
Exactly.

With limited info that reads like the OP was new to reloading and now some bullets are loose in some brass (mix of old and new), my first thought was annealing, not thin walled brass.

Glad the OP found out what he has. It’s easy from here.

OP: I use both .267 and .266 in my 6BR and 6GT. Cannot remember what I’m using in my 6BR with Lapua brass. One of those. 🫣 Probably .267.
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Thank you, that is good to know! I will try the 267 and see what it looks like.
 
I Dont Care About You said:
The amount of stupid in this thread is just SHOCKING.

All the people advocating to push the shoulder back, please explain how the headspace relates to the neck dimension ........... I'll wait.
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From what I recall the OP stated he had a standard die with an expander ball.
If the recapping rod was set a bit deeper than it needed to be and the die set a bit higher than it should be, then he would not be sizing the case properly .
Now we learn that he has a bushing die.
He simply needs to go down one size in bushings.
Cat
 
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BigBraz15 said:
It is not a bushing die currently, it is a full length die.
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There are full-length bushing dies .... which you seem to have discovered now.


BigBraz15 said:
I was pondering on this one today, and it isn’t clicking how bumping the shoulder will change the diameter of the neck. Am I missing anything here?
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Nope you are not.


BigBraz15 said:
I just opened up my die, and to my surprise it IS a bushing die. Redding .268

I am assuming if I go down to a .267 I should be okay?
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I'd go down to .266 for a little extra neck tension.

Make sure to remove the expander ball or the smaller bushing won't make a difference. Bushing dies always come with a non-expanding retainer to keep the decapping pin in place.

Removing the expander ball also helps with neck concentricity and neck stretch.

Note: when installing the decapping assy, run it in till it bottoms on the bushing and then turn it out 1/8 turn so the bushing is just slightly loose. That allows the bushing to self centre on the case neck, which reduces runout.
 
I Dont Care About You said:
There are full-length bushing dies .... which you seem to have discovered now.



Nope you are not.



I'd go down to .266 for a little extra neck tension.

Make sure to remove the expander ball or the smaller bushing won't make a difference. Bushing dies always come with a non-expanding retainer to keep the decapping pin in place.

Removing the expander ball also helps with neck concentricity and neck stretch.

Note: when installing the decapping assy, run it in till it bottoms on the bushing and then turn it out 1/8 turn so the bushing is just slightly loose. That allows the bushing to self centre on the case neck, which reduces runout.
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Thank you. I appreciate all of the info on this one. There is no expander ball on this, just a well undersized decapping assembly. I picked up both 267 and 266 bushings, I tried the 267 on 5 cases, and they all seemed good. I will monitor and see what the results look like.

Good info on backing it off 1/8 of a turn, I was not aware of that.
 
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