Over pressure signs
- Thread starter boisblancboy
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CatShooter
New member
Originally Posted By: SShooterZIf you get a chance, read Pet Loads by Ken Waters.
He has an interesting, and I think accurate, perspective and method for discovering high pressure loads using the case head expansion.
It's not perfect, but I think it is more accurate than reading a primer.
I know about the case expansion "method"... there is no science behind it. Case heads vary in hardness, even in the same lot, and there is no way to make any meaning of it.
And what does 1thou of expansion mean - and where did they come up with that number???
They just picked it because their mics read to 0.001"
Also, rifles don't fail at the case head, so case head expansion is meaningless. The amount that they expand has little to do with anything.
They fail at the primer, so that is where you look for signs of possible approaching failure.
.
He has an interesting, and I think accurate, perspective and method for discovering high pressure loads using the case head expansion.
It's not perfect, but I think it is more accurate than reading a primer.
I know about the case expansion "method"... there is no science behind it. Case heads vary in hardness, even in the same lot, and there is no way to make any meaning of it.
And what does 1thou of expansion mean - and where did they come up with that number???
They just picked it because their mics read to 0.001"
Also, rifles don't fail at the case head, so case head expansion is meaningless. The amount that they expand has little to do with anything.
They fail at the primer, so that is where you look for signs of possible approaching failure.
.
CatShooter
New member
Originally Posted By: MPFDGood question should neck sizing dies not cam over like an RCBS full length size die?
It doesn't make any difference... and most people that neck size, only size part of the neck.
You screw the die down until it sizes the amount you want.
.
It doesn't make any difference... and most people that neck size, only size part of the neck.
You screw the die down until it sizes the amount you want.
.
zilla
New member
There is a great article by James Calhoon on preassure here.. http://www.jamescalhoon.com/
CatShooter
New member
Originally Posted By: ARCOREYOriginally Posted By: CatShooter
Every time you touch the shoulder with a FL or Bump die, you create headspace.
For the rifles that I use for varmints, I prefer a "Crush" feel when I close the bolt - that is a negative headspace, and cases will last forever. I have ~300 pieces of Rem 22-250 that are on their 6th barrel (maybe 10,000-12,000 firings - 40 firings each), and they are as good as when they were first fired.
.
To make sure I understand this right because I'm on a new barrel and want to make the most of it and my brass. After fire forming my brass, I should be able to reset my FL dies or neck dies and only decap the brass and flare the mouth and and not even touch the shoulder? I try and keep my neck dies off the shoulder now and set my FL dies per Reddings recommended procedure of camming over on the shell holder. It sounds like I shouldn't ever need my FL die again after I get them fired in my chamber or for my 2 die sets, never need a neck die.
I'm also gauging my trim length with one of the neck pilots from sinclair that you soft seat in a fired case that is trimmed short. My Lapua brass doesn't seem to grow much at all in my 243. I've yet to get it to where I'm close in my old factory barrel or my new barrel of my 243. Am I listening too much to the wives tales crowd about case stretch in a 243, or am I lucky? I'm hitting atleast 5 firings and still not getting to the gauge length on any of my 200 Lapuas and only chamfer and deburred them from day one.
This has been an informative post. Thanks to all the contributors.
The first firing in a new chamber is the most critical time in a case's life - it is where the damage is done (or not done) and determines the rest of case's life.
The case can stretch and be weakened, or it can fill the chamber without stretching, and then last almost forever.
Here's what I DON'T do,
I do not deburr or chamfer - never ever!
I do not use the expander in the sizing die - never!
Here's what I do.
For each serious caliber I get, I have a... :
Forster Ultra die set (FL and Ultra-match seater).
A Redding bushing sizer die (but a regular Forster neck sizer can do - more on that later).
A Lyman "M" die.
Plus, I already have a set (of three) Redding universal decaping dies.
---
The first firing in a new chamber is the most critical moment in a cases life. That firing will determine the life of the case.
When a case is fired in a new chamber for the first time, it is a loose fit, and the primer forces it forward and slams it into the chamber's shoulder. At this first firing, there can be as much as 20 thou or more of head space, regardless of what SAAMI says.
When the case is slammed forward, there are two possible outcomes:
1 - when the pressure builds, the case walls expand and grab the chamber walls... then the pressure continues to climb, and the thin section of the case, just in front of the head (called the web) can't hold the pressure anymore, so it stretches - the body is firmly stuck to the chamber walls, and the case head goes back and hits the bolt face. Now we have a case with a thin section just in front of the head - a very badd thing. Now the case is weakened and will never be a good case, even though it may take 4 or 5 firings to fail - it WILL fail, it cannot be fixed.
or
2 - when the pressure builds, the case walls expand and cannot grab the chamber walls.
And, because the chamber and case cannot get a grip on each other, the whole case immediately slides back to the bolt face, and contains the pressure - it does not stretch, and so there is no thin section in front of the web, and it is a strong case forever (or until you screw it up).
Now, if you have a cheap rifle, and use range pick-up brass and don't care, then don't bother to read the rest of this, cuz it's gonna bore the crap out of you...
... but if you are paying top dollar for Lapua or Norma brass, or have a wildcat and are investing time in case prep, then stay on for the rest.
---
That is the option on how we start the life of our cases - and with cases costing what they do now, it is worth considering - I have 1,100 Lapua cases for my 6mmBR - at around $800 to $1,000, that's a BIG investment, not counting the countless hours it to neck turn all those damm cases, and then anneal them
---
For the first loading (assuming that it is new brass)...
1 - I use the Lyman "M" die to expand the neck and put a "tiny" flair to the mouth. Just enough to allow the bullet to start. Adjust the expander stem to make a small flair - just enough that the bullet will sit there on it's own, and not fall over.
If there is some brass that is uneven at the mouth, or a tiny rim around the mouth, don't worry now, fix it later, after the case has been fired the first time.
I load one case with a bullet - and measure the neck OD - lets say it is a 6mm Rem (cuz that's what I am working on now). The bullet dia is .243, and the neck OD is 0.271". I pack the FL die off to Forster, with a check for $12, and tell them I want the neck diamond honed to 0.268" that is 3 thou smaller than the loaded neck dia - and it comes back in a week
I pull the single bullet, and now I load normal testing sequence (while the dies is on the way to Forster), and shoot it, looking for the usual suspects.
I do NOT beat up the cases - when I see what I think is upper pressure signs for that gun, I quit - I don't keep going, "just to see how high I can go". I pull the ones I don't shoot.
Now, this is important... for the first firing, I give the case a light coat of oil, like G-96 (it smells good). I use a Lyman lube pad, soaked in G-96. Get a little on the shoulder and neck too.
I fire the case, and it fills the chamber without stretching, cuz the case walls cannot grab the chamber walls.
The case slides back firmly against the bolt face, before the pressure has reached maximum. The case will fill out the chamber without stretching. This is a perfect start for the case.
Now, I deprime with the universal decapping die.
At this time, I measure 10 or 15 cases for overall length - I pick the shortest, and if it is less than the maximum SAAMI length, I trim it JUST ENOUGH to clean up the mouth all around - then I trim all the rest the same length. IF it is over SAAMI max, I trim all of them to SAAMI max.
So now, my cases tightly fit the chamber and are as long as then can be and still be within SAAMI.
Now... if I have a bushing neck sizer, I use that. If not, I use my Forster FL die that has just come back and has a custom neck diameter
Now, I neck size the case, JUST the amount that the base will sit in the neck. If the bullet will go to the bottom of the neck, I size the whole neck, if possible... but I do NOT let the die hit the shoulder no matter what, and if it hits the body, I stop there. With a bushing die, there is no worries, and you CAN get a Forster neck die, and have the same custom honing done to it.
So the fired case has been neck sized. Now I use the Lyman "M" die to expand the neck and put a "tiny" flair to the mouth. If the "M" die doesn't flair the mouth anymore, cuz the case has been trimmed, then adjust the die again. Just enough to allow the bullet to start.
So at this point, we have quality cases, that have been made to fit the chamber without stretching or damage, and we have loading stuff to load the cases with the very least amount of disruption of the brass - anneal the mouths and shoulders every so often - 5 to 8 firings, and anneal all the cases at the same time.
---
Now... we have shot the crap out of that barrel, and just got a new barrel in the same caliber - what do we do.
Try to chamber a fired case - if it goes in to the chamber and there is a fair amount of effort to close the bolt, then goodie - just load the cases, lube them and shoot them.
But if it is sooo tight that you can't chamber it, then use the FL die.
Here's how to adjust it. Lube the case and start sizing the case in teeny tiny amounts - people talk about turning a die 1/4 of a turn - not here - turn the die 1/40th of a turn, size a case and try to chamber it. If it doesn't go, turn the die down another 1/40th and try with a DIFFERENT case, and try to chamber it - keep doing this until you can get the bolt to close with effort.
Then size all the cases.
Now, you start all over again. Lube the loaded cases on the pad, and fire them... when you fire the tight cases, they will re-form to the new chamber, and then be easier to chamber.
If... the old cases slide into the new chamber without any resistance (the new chamber is larger than the old one), then just lube them and shoot them, they will fill the new chamber, just like they did the first time you fired them, and you can start all over again.
I hope this makes some kinda sense...
.
Every time you touch the shoulder with a FL or Bump die, you create headspace.
For the rifles that I use for varmints, I prefer a "Crush" feel when I close the bolt - that is a negative headspace, and cases will last forever. I have ~300 pieces of Rem 22-250 that are on their 6th barrel (maybe 10,000-12,000 firings - 40 firings each), and they are as good as when they were first fired.
.
To make sure I understand this right because I'm on a new barrel and want to make the most of it and my brass. After fire forming my brass, I should be able to reset my FL dies or neck dies and only decap the brass and flare the mouth and and not even touch the shoulder? I try and keep my neck dies off the shoulder now and set my FL dies per Reddings recommended procedure of camming over on the shell holder. It sounds like I shouldn't ever need my FL die again after I get them fired in my chamber or for my 2 die sets, never need a neck die.
I'm also gauging my trim length with one of the neck pilots from sinclair that you soft seat in a fired case that is trimmed short. My Lapua brass doesn't seem to grow much at all in my 243. I've yet to get it to where I'm close in my old factory barrel or my new barrel of my 243. Am I listening too much to the wives tales crowd about case stretch in a 243, or am I lucky? I'm hitting atleast 5 firings and still not getting to the gauge length on any of my 200 Lapuas and only chamfer and deburred them from day one.
This has been an informative post. Thanks to all the contributors.
The first firing in a new chamber is the most critical time in a case's life - it is where the damage is done (or not done) and determines the rest of case's life.
The case can stretch and be weakened, or it can fill the chamber without stretching, and then last almost forever.
Here's what I DON'T do,
I do not deburr or chamfer - never ever!
I do not use the expander in the sizing die - never!
Here's what I do.
For each serious caliber I get, I have a... :
Forster Ultra die set (FL and Ultra-match seater).
A Redding bushing sizer die (but a regular Forster neck sizer can do - more on that later).
A Lyman "M" die.
Plus, I already have a set (of three) Redding universal decaping dies.
---
The first firing in a new chamber is the most critical moment in a cases life. That firing will determine the life of the case.
When a case is fired in a new chamber for the first time, it is a loose fit, and the primer forces it forward and slams it into the chamber's shoulder. At this first firing, there can be as much as 20 thou or more of head space, regardless of what SAAMI says.
When the case is slammed forward, there are two possible outcomes:
1 - when the pressure builds, the case walls expand and grab the chamber walls... then the pressure continues to climb, and the thin section of the case, just in front of the head (called the web) can't hold the pressure anymore, so it stretches - the body is firmly stuck to the chamber walls, and the case head goes back and hits the bolt face. Now we have a case with a thin section just in front of the head - a very badd thing. Now the case is weakened and will never be a good case, even though it may take 4 or 5 firings to fail - it WILL fail, it cannot be fixed.
or
2 - when the pressure builds, the case walls expand and cannot grab the chamber walls.
And, because the chamber and case cannot get a grip on each other, the whole case immediately slides back to the bolt face, and contains the pressure - it does not stretch, and so there is no thin section in front of the web, and it is a strong case forever (or until you screw it up).
Now, if you have a cheap rifle, and use range pick-up brass and don't care, then don't bother to read the rest of this, cuz it's gonna bore the crap out of you...
... but if you are paying top dollar for Lapua or Norma brass, or have a wildcat and are investing time in case prep, then stay on for the rest.
---
That is the option on how we start the life of our cases - and with cases costing what they do now, it is worth considering - I have 1,100 Lapua cases for my 6mmBR - at around $800 to $1,000, that's a BIG investment, not counting the countless hours it to neck turn all those damm cases, and then anneal them
---
For the first loading (assuming that it is new brass)...
1 - I use the Lyman "M" die to expand the neck and put a "tiny" flair to the mouth. Just enough to allow the bullet to start. Adjust the expander stem to make a small flair - just enough that the bullet will sit there on it's own, and not fall over.
If there is some brass that is uneven at the mouth, or a tiny rim around the mouth, don't worry now, fix it later, after the case has been fired the first time.
I load one case with a bullet - and measure the neck OD - lets say it is a 6mm Rem (cuz that's what I am working on now). The bullet dia is .243, and the neck OD is 0.271". I pack the FL die off to Forster, with a check for $12, and tell them I want the neck diamond honed to 0.268" that is 3 thou smaller than the loaded neck dia - and it comes back in a week
I pull the single bullet, and now I load normal testing sequence (while the dies is on the way to Forster), and shoot it, looking for the usual suspects.
I do NOT beat up the cases - when I see what I think is upper pressure signs for that gun, I quit - I don't keep going, "just to see how high I can go". I pull the ones I don't shoot.
Now, this is important... for the first firing, I give the case a light coat of oil, like G-96 (it smells good). I use a Lyman lube pad, soaked in G-96. Get a little on the shoulder and neck too.
I fire the case, and it fills the chamber without stretching, cuz the case walls cannot grab the chamber walls.
The case slides back firmly against the bolt face, before the pressure has reached maximum. The case will fill out the chamber without stretching. This is a perfect start for the case.
Now, I deprime with the universal decapping die.
At this time, I measure 10 or 15 cases for overall length - I pick the shortest, and if it is less than the maximum SAAMI length, I trim it JUST ENOUGH to clean up the mouth all around - then I trim all the rest the same length. IF it is over SAAMI max, I trim all of them to SAAMI max.
So now, my cases tightly fit the chamber and are as long as then can be and still be within SAAMI.
Now... if I have a bushing neck sizer, I use that. If not, I use my Forster FL die that has just come back and has a custom neck diameter
Now, I neck size the case, JUST the amount that the base will sit in the neck. If the bullet will go to the bottom of the neck, I size the whole neck, if possible... but I do NOT let the die hit the shoulder no matter what, and if it hits the body, I stop there. With a bushing die, there is no worries, and you CAN get a Forster neck die, and have the same custom honing done to it.
So the fired case has been neck sized. Now I use the Lyman "M" die to expand the neck and put a "tiny" flair to the mouth. If the "M" die doesn't flair the mouth anymore, cuz the case has been trimmed, then adjust the die again. Just enough to allow the bullet to start.
So at this point, we have quality cases, that have been made to fit the chamber without stretching or damage, and we have loading stuff to load the cases with the very least amount of disruption of the brass - anneal the mouths and shoulders every so often - 5 to 8 firings, and anneal all the cases at the same time.
---
Now... we have shot the crap out of that barrel, and just got a new barrel in the same caliber - what do we do.
Try to chamber a fired case - if it goes in to the chamber and there is a fair amount of effort to close the bolt, then goodie - just load the cases, lube them and shoot them.
But if it is sooo tight that you can't chamber it, then use the FL die.
Here's how to adjust it. Lube the case and start sizing the case in teeny tiny amounts - people talk about turning a die 1/4 of a turn - not here - turn the die 1/40th of a turn, size a case and try to chamber it. If it doesn't go, turn the die down another 1/40th and try with a DIFFERENT case, and try to chamber it - keep doing this until you can get the bolt to close with effort.
Then size all the cases.
Now, you start all over again. Lube the loaded cases on the pad, and fire them... when you fire the tight cases, they will re-form to the new chamber, and then be easier to chamber.
If... the old cases slide into the new chamber without any resistance (the new chamber is larger than the old one), then just lube them and shoot them, they will fill the new chamber, just like they did the first time you fired them, and you can start all over again.
I hope this makes some kinda sense...
.
SShooterZ
New member
Originally Posted By: CatShooterI know about the case expansion "method"... there is no science behind it. Case heads vary in hardness, even in the same lot, and there is no way to make any meaning of it.
And what does 1thou of expansion mean - and where did they come up with that number???
They just picked it because their mics read to 0.001"
I don't claim to be an expert, so take it for what it is worth.
My understanding is that the whole process was to be used as a comparison. If the case measured "X" before and "X+" after, you would start to know when you were getting near the max for that particular load. Nothing more, nothing less. More of a comfort zone measurement anyway, not an exact number and not an actual "reading" of pressure. I don't believe that Waters put a specific number on his measurements either. The practice is to track for lack of a better word, where your case is growing and at what charge. It obviously will not tell you the PSI at which you're operating at.
After reading Calhoon's article, I think you might be confusing the two. Calhoon mentions .0001 as the peak point. Why, I have no idea.
Personally, other than testing in a piezo-electric transducer you're never going to get an exact PSI for your loads. You look for signs and how you interpret those signs will tell you if you are comfortable with the pressures your loads are creating.
One other tool that can be handy but is again, not specific, is a chronograph. If you can get moderate case expansion, not blow out primers and avoid hard extraction and yet hit the velocities you want, then you can stop right there and not tempt fate.
And what does 1thou of expansion mean - and where did they come up with that number???
They just picked it because their mics read to 0.001"
I don't claim to be an expert, so take it for what it is worth.
My understanding is that the whole process was to be used as a comparison. If the case measured "X" before and "X+" after, you would start to know when you were getting near the max for that particular load. Nothing more, nothing less. More of a comfort zone measurement anyway, not an exact number and not an actual "reading" of pressure. I don't believe that Waters put a specific number on his measurements either. The practice is to track for lack of a better word, where your case is growing and at what charge. It obviously will not tell you the PSI at which you're operating at.
After reading Calhoon's article, I think you might be confusing the two. Calhoon mentions .0001 as the peak point. Why, I have no idea.
Personally, other than testing in a piezo-electric transducer you're never going to get an exact PSI for your loads. You look for signs and how you interpret those signs will tell you if you are comfortable with the pressures your loads are creating.
One other tool that can be handy but is again, not specific, is a chronograph. If you can get moderate case expansion, not blow out primers and avoid hard extraction and yet hit the velocities you want, then you can stop right there and not tempt fate.
CatShooter
New member
Originally Posted By: pcammoOriginally Posted By: CatShooter
You screw the die down until it sizes the amount you want.
.
It really is that simple.... and yet most folks don't even measure their brass to know how much they are setting back the shoulder.
If you are neck sizing - you are not touching the shoulder.
You screw the die down until it sizes the amount you want.
.
It really is that simple.... and yet most folks don't even measure their brass to know how much they are setting back the shoulder.
If you are neck sizing - you are not touching the shoulder.
CatShooter
New member
Originally Posted By: pcammo
I guess I lost track of the original question.
It was about cooking and eating woodchucks
I guess I lost track of the original question.
It was about cooking and eating woodchucks
CatShooter
New member
Originally Posted By: Hooked^^^good post..now I need to go out and get some G96 just to see what it smells like...anything like tri-flow?
Oh, MUCH better than most everything - even give the old Hoppe's #9 a run for it's money.
Get the spray oil, not the synthetic stuff.
Oh, MUCH better than most everything - even give the old Hoppe's #9 a run for it's money.
Get the spray oil, not the synthetic stuff.
CatShooter
New member
Originally Posted By: shanedoggcatshooter seems to know his shizz, very interesting read, however if i followed this process, with the time i have, i would load about 12 rounds a year...lol...
Oh, I do a lot more than 12 rounds a year
Oh, I do a lot more than 12 rounds a year
Hooked
New member
Originally Posted By: shanedoggcatshooter seems to know his shizz, very interesting read, however if i followed this process, with the time i have, i would load about 12 rounds a year...lol...
Agreed, I can definately tell there is a high level of experience. Trouble is (in my case anyhow) I tend to learn better with `hands on experience`. I`m greatful to the friend who helped/mentored me in the beginning, but not much more than just the basics.
There is a fellow here local to me who has been a competitive BR shooter for years (successful too acording to the large quantity of trophy`s he`s aquired)and has offered to spend some time with me, but it`s just a matter of finding the time to do so.
I understand there is a great deal depends on the equipment (rifle)and technique (person behind the trigger) but surely quality reloads must be part of the equation too.
I will have to go back and read a couple post again to comprehend a little more, but one thing that stuck out to me was not chamfering but using an expander.
Better than tri-flow...IDK!!
Agreed, I can definately tell there is a high level of experience. Trouble is (in my case anyhow) I tend to learn better with `hands on experience`. I`m greatful to the friend who helped/mentored me in the beginning, but not much more than just the basics.
There is a fellow here local to me who has been a competitive BR shooter for years (successful too acording to the large quantity of trophy`s he`s aquired)and has offered to spend some time with me, but it`s just a matter of finding the time to do so.
I understand there is a great deal depends on the equipment (rifle)and technique (person behind the trigger) but surely quality reloads must be part of the equation too.
I will have to go back and read a couple post again to comprehend a little more, but one thing that stuck out to me was not chamfering but using an expander.
Better than tri-flow...IDK!!
ARCOREY
New member
Thanks Catshooter. I seem to fall in the bottom portion of the cases won't fit the new chamber right now. I always welcome knowledge and appreciate you taking the time to explain the process. I probably fall into the 95% category of reloaders that never knew half what you just explained and have reloaded for years wasting material and risking case head seperation and injury. This part confuses me a little though.
"I load one case with a bullet - and measure the neck OD - lets say it is a 6mm Rem (cuz that's what I am working on now). The bullet dia is .243, and the neck OD is 0.271". I pack the FL die off to Forster, with a check for $12, and tell them I want the neck diamond honed to 0.268" that is 3 thou smaller than the loaded neck dia - and it comes back in a week."
I'm not sure how this works without neck turning, or does it? How can you get 0.271" every time, or is the premium brass that consistent that it won't matter. The prep from new makes sense to me. Hopefully I haven't degraded my 200 Lapua cases in the early part of their life to hurt them enough to follow the latter part of your prep regimen for the new chamber. I've saved the post for future reference. Thanks again.
"I load one case with a bullet - and measure the neck OD - lets say it is a 6mm Rem (cuz that's what I am working on now). The bullet dia is .243, and the neck OD is 0.271". I pack the FL die off to Forster, with a check for $12, and tell them I want the neck diamond honed to 0.268" that is 3 thou smaller than the loaded neck dia - and it comes back in a week."
I'm not sure how this works without neck turning, or does it? How can you get 0.271" every time, or is the premium brass that consistent that it won't matter. The prep from new makes sense to me. Hopefully I haven't degraded my 200 Lapua cases in the early part of their life to hurt them enough to follow the latter part of your prep regimen for the new chamber. I've saved the post for future reference. Thanks again.
JerrySchmitt
New member
Originally Posted By: CatShooter
ARCOREY said:
CatShooter
New member
Originally Posted By: ARCOREY
"... This part confuses me a little though.
"I load one case with a bullet - and measure the neck OD - lets say it is a 6mm Rem (cuz that's what I am working on now). The bullet dia is .243, and the neck OD is 0.271". I pack the FL die off to Forster, with a check for $12, and tell them I want the neck diamond honed to 0.268" that is 3 thou smaller than the loaded neck dia - and it comes back in a week."
I'm not sure how this works without neck turning, or does it? How can you get 0.271" every time, or is the premium brass that consistent that it won't matter. The prep from new makes sense to me. Hopefully I haven't degraded my 200 Lapua cases in the early part of their life to hurt them enough to follow the latter part of your prep regimen for the new chamber. I've saved the post for future reference. Thanks again."
Ok... I'll try to make this clearer.
The reason you measure the neck diameter at this point is to know who much you want Forster to hone the neck of the die.
The average medium to large bore case has case neck walls that are 0.0140" to 0.0145"... but they can be as small as 0.0120".
We are not turning here, we are just trying to find an approximation of the loaded neck dia - we could have picked a different case, and it might have given us a measurement of 0.272" or 0.270", but in either measurement, when the die neck is honed, we have a die that will minimally size the neck.
Reason being that more regular dies (RCBS, etc) over size the neck so much that the neck work hardens in one or two sizing - with a neck sizing die that only brings the neck down 3 to 4 thou... and then we expand with the Lyman "M" die, the neck brass does not get beat up.
So it is not like we were turning - we don't need that much precision at this point.
Does it make more sense now?
"... This part confuses me a little though.
"I load one case with a bullet - and measure the neck OD - lets say it is a 6mm Rem (cuz that's what I am working on now). The bullet dia is .243, and the neck OD is 0.271". I pack the FL die off to Forster, with a check for $12, and tell them I want the neck diamond honed to 0.268" that is 3 thou smaller than the loaded neck dia - and it comes back in a week."
I'm not sure how this works without neck turning, or does it? How can you get 0.271" every time, or is the premium brass that consistent that it won't matter. The prep from new makes sense to me. Hopefully I haven't degraded my 200 Lapua cases in the early part of their life to hurt them enough to follow the latter part of your prep regimen for the new chamber. I've saved the post for future reference. Thanks again."
Ok... I'll try to make this clearer.
The reason you measure the neck diameter at this point is to know who much you want Forster to hone the neck of the die.
The average medium to large bore case has case neck walls that are 0.0140" to 0.0145"... but they can be as small as 0.0120".
We are not turning here, we are just trying to find an approximation of the loaded neck dia - we could have picked a different case, and it might have given us a measurement of 0.272" or 0.270", but in either measurement, when the die neck is honed, we have a die that will minimally size the neck.
Reason being that more regular dies (RCBS, etc) over size the neck so much that the neck work hardens in one or two sizing - with a neck sizing die that only brings the neck down 3 to 4 thou... and then we expand with the Lyman "M" die, the neck brass does not get beat up.
So it is not like we were turning - we don't need that much precision at this point.
Does it make more sense now?
ARCOREY
New member
Gotcha. Well, looks like I've got some future shopping to do. I wished I had asked these questions before I got the new barreled action back so I'd have gotten my scat together before the gophering commenced for the summer. Looks like I may run the 243 with the brass I have for now and start acquiring the goods through the summer so I'll have a winter project. Hopefully I can snag some more good brass for next year or salvage mine with this new approach. This has been very informative. Thanks again
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boisblancboy
New member
I have a feeling this post might continue on for awhile yet, which is great cause all this information is invaluable! Thanks for everyone that has posted.