FL sizing ?

WhiteOak

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Oct 10, 2014
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If a once fired 3006 case is still in spec with length and the shoulder , when the die is set up and you run the case up, is it being FL sized or is it neck sizing only since there is nothing to change with the case except for neck tension ?
 

Bigeclipse

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If a once fired 3006 case is still in spec with length and the shoulder , when the die is set up and you run the case up, is it being FL sized or is it neck sizing only since there is nothing to change with the case except for neck tension ?

Full length dies also squeeze the case body back to SAMMI spec
 

Bill Johnson

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Sep 27, 2014
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If a once fired 3006 case is still in spec with length and the shoulder , when the die is set up and you run the case up, is it being FL sized or is it neck sizing only since there is nothing to change with the case except for neck tension ?

It appears you might be operating under the assumption that nothing has changed dimensionally on the case after being fired. That is never the case.

Unless, on chambering, you are crush-fitting the cartridge in the chamber, it should (will) grow, if only ever so slightly.

It has to have clearance in the chamber.
Upon firing, it expands, first at the neck sealing the chamber, then the body expands laterally to fill the chamber circumferentially, then, as maximum pressure is reached, the case head is forced aft, stretching the case. It may appear to fit a case gage the same, and with dies set up for minimal sizing, will limit growth to .001 or so, but it will grow.

Current practice is to set up dies for bolt rifles so the shoulder is set back .002" during sizing to provide for proper chambering but limit case stretching. Autoloaders, it's recommended to set back shoulders .003 - .004.

An effective way to measure shoulder position is to use an appropriate size bushing and a caliper:



For the 30-06, a standard 3/8" bushing from Home Depot or Lowes fits the bill perfectly.

You measure the case as shown before and after firing. In this instance, the case shoulder-to-case head distance increased .003.

If I'm way off base on this, WhiteOak, just let me know. It wouldn't be the first time I went on and on about something unrelated to an OP's post. :D
 

WhiteOak

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I have my equipment to reload but I haven't started yet. I'm new .
OK , for 3006. Unfired fed. case - 2.042"
Rem. unfired 2.042"
Rem. once fired 2.042 "

A Winchester that's new from a bag is 2.036

SAAMI has max of 2.0587" and min. of 2.0487"

So second part of my question is , what is excessive head space ? How much set back is that ?
 

Bill Johnson

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Sep 27, 2014
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Could you tell me what the actual dimension of that bushing is? Thanks.

Rich

Rich, this is the item:

Crown Bolt 3/8 in. x 5/8 in. x 1 in. Bronze Flange Bearing-57738 - The Home Depot

Mine is buried in a storage shed right now. The inside mics right at .375 and has a slight bevel.

While the 30-06 SAAMI specifications call out .375 at the datum, it's just lucky happenstance but not that critical in that the idea is not to attempt to determine actual distance from datum-to-case head face, but to take a differential reading between fired and unfired cases.

The same bushing serves the purpose on the 308 family of cases even though the datum is somewhere in the .400 range.
 

Bill Johnson

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102
I have my equipment to reload but I haven't started yet. I'm new .
OK , for 3006. Unfired fed. case - 2.042"
Rem. unfired 2.042"
Rem. once fired 2.042 "

A Winchester that's new from a bag is 2.036

SAAMI has max of 2.0587" and min. of 2.0487"

So second part of my question is , what is excessive head space ? How much set back is that ?

I see you have another post along these lines. First I would say is that I successfully loaded hundreds of thousands of rounds before ever hearing about or measuring cartridges in this manner, long before the internet or the introduction of tools such as the Hornady cartridge gage.

Firearm chambers have headspace, cartridges do not. Headspace is the distance from the breech face, with locking lugs/mechanism loaded, to the chamber datum for a specific cartridge.

It appears that you are using a tool, such as the Hornady tool, to measure from the cartridge head to the datum. While nice to know, it tells you nothing about the chamber except how much it is allows the case head-to-datum line to increase with each firing, and that's dependent on pressure developed in the case as well as case condition (metallurgical properties).

Given your measurements, about all that can be definitely said is that the Winchester brass will end up stretching the most.

As far as the difference between your case measurements and SAAMI chamber specifications, there is no "excessive" amount. In a 30-06 rifle with a good extractor, such as a Mauser or Springfield, a 308 Winchester cartridge can be safely fired and all you will end up with is a straight wall case marked 308!

The difference between your cases and actual chamber dimensions will affect case life. Cases sized or resized to SAAMI minimums, shot in a chamber cut to maximums or even worn beyond will exhibit the shortest case life in high pressure loads. I had this situation when I first started out. An old 30-30 with cases resized in dies set up per RCBS instructions only lasted 4-5 firings before I'd see signs of a imminent case head separation.

That is what your tool is for: Not to determine headspace but to determine how best to set your dies up. For best case life, you want to "bump" the shoulder back (which is where the datum line is on most bottle neck, non-rimmed or belted cases) .002 from what a fired case measures.

The .002 allows minimum clearance to ensure easy chambering while minimizing case growth / maximizing case life.

Whew! JFYI, I usually make about $150 in salary for the time it took to type all this. :)

P.S. And it's not because I'm that slow a typist!:D
 

WhiteOak

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Oct 10, 2014
Messages
107
I see you have another post along these lines. First I would say is that I successfully loaded hundreds of thousands of rounds before ever hearing about or measuring cartridges in this manner, long before the internet or the introduction of tools such as the Hornady cartridge gage.

Firearm chambers have headspace, cartridges do not. Headspace is the distance from the breech face, with locking lugs/mechanism loaded, to the chamber datum for a specific cartridge.

It appears that you are using a tool, such as the Hornady tool, to measure from the cartridge head to the datum. While nice to know, it tells you nothing about the chamber except how much it is allows the case head-to-datum line to increase with each firing, and that's dependent on pressure developed in the case as well as case condition (metallurgical properties).

Given your measurements, about all that can be definitely said is that the Winchester brass will end up stretching the most.

As far as the difference between your case measurements and SAAMI chamber specifications, there is no "excessive" amount. In a 30-06 rifle with a good extractor, such as a Mauser or Springfield, a 308 Winchester cartridge can be safely fired and all you will end up with is a straight wall case marked 308!

The difference between your cases and actual chamber dimensions will affect case life. Cases sized or resized to SAAMI minimums, shot in a chamber cut to maximums or even worn beyond will exhibit the shortest case life in high pressure loads. I had this situation when I first started out. An old 30-30 with cases resized in dies set up per RCBS instructions only lasted 4-5 firings before I'd see signs of a imminent case head separation.

That is what your tool is for: Not to determine headspace but to determine how best to set your dies up. For best case life, you want to "bump" the shoulder back (which is where the datum line is on most bottle neck, non-rimmed or belted cases) .002 from what a fired case measures.

The .002 allows minimum clearance to ensure easy chambering while minimizing case growth / maximizing case life.

Whew! JFYI, I usually make about $150 in salary for the time it took to type all this. :)

P.S. And it's not because I'm that slow a typist!:D
I don't mean to be a pain but a non fired case and a once fired case are at 2.042. Would I not set the die to this ?
 

sedancowboy

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Nov 28, 2014
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White Oak
The post by Bill is spot on and very correct. It appears that all that went right over your head (no offense intended). The dimensions you gave in your post are confusing us and
don't appear to be the Length of a 30-06 which is 2.494 max. Base to datum line would be much greater than the cartridge length (as measured with a comparator as Bill showed) and the number don't matter you are only comparing the new unfired case to a fired case and measuring how much it grew after firing. Then taking the fired case dimension and sizing you case back until it is about .002-.003 shorter at the datum line. If you run the case into the die until the shell holder hits the bottom of the die, that will be back to unfired dimension and will shorten your case life and may not be as accurate as a properly sized case that fits your rifle.
May I suggest you purchase a good reloading manual or 2 and read the front section
The Hornady that I am looking at has a very good explanation of reloading. Others are good as well. Pick your brand and buy one.

Remember there are no dumb questions only dumb answers.
 

muddydogs

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Feb 26, 2015
Messages
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Location
Utah
First forget the unfired case as the measurements have nothing to do with your rifle. If you have a fired case from your rifle and it measures 2.042 then adjust the die to set the case back to 2.040. These numbers are right in line with the 2 30-06's I load for.

You also have to remember that the gauge you are using may not be exact as it is a mass produced piece of aluminum but for what we do with it it will work just fine. Your numbers might not be the same as other peoples numbers due to the gauge but your numbers are all that matter.
 

WhiteOak

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Oct 10, 2014
Messages
107
First forget the unfired case as the measurements have nothing to do with your rifle. If you have a fired case from your rifle and it measures 2.042 then adjust the die to set the case back to 2.040. These numbers are right in line with the 2 30-06's I load for.

You also have to remember that the gauge you are using may not be exact as it is a mass produced piece of aluminum but for what we do with it it will work just fine. Your numbers might not be the same as other peoples numbers due to the gauge but your numbers are all that matter.
Thanks muddydogs ,when your on your own and no one around that reloads and reading manuals , there are many un answered questions .

Thanks to Bill Johnson too !
 

RichinVA

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Feb 7, 2015
Messages
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Location
VA
Rich, this is the item:

Crown Bolt 3/8 in. x 5/8 in. x 1 in. Bronze Flange Bearing-57738 - The Home Depot

Mine is buried in a storage shed right now. The inside mics right at .375 and has a slight bevel.

While the 30-06 SAAMI specifications call out .375 at the datum, it's just lucky happenstance but not that critical in that the idea is not to attempt to determine actual distance from datum-to-case head face, but to take a differential reading between fired and unfired cases.

The same bushing serves the purpose on the 308 family of cases even though the datum is somewhere in the .400 range.

Understand, needed the dim. for a different project. Would agree with your assessment, all things considered. Thanks.

Rich
 
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