I seriously doubt this is case head separation but what do you guys think?

[Lonewolf74]

I'm using hornday comparator guage to measure the shoulder

Yes but what is the actual measurement?
I know it's not .626 from base to shoulder, do you mean 1.626?

 

[bigedp51]

J E CUSTOM

You don't know what you think you know.

Not only did I collect the Enfield rifle I also collected all the military manuals and books on the Enfield rifle. And at one time had the largest Enfield manual sticky in two Enfield forums anywhere on the Internet.

Below are the British headspace gauges and limits directly from the British manual dated 1957.

SM 139- Gauge, Armourer's, headspace, chamber accept, 0.064 inch No1
SM 140- Gauge, Armourer's, headspace, chamber reject, 0.074 inch Royal If bolt closes on SM140--Shant fire!

Below from the British 1931 Instruction for Armourers
4. Action:—Bolt and bolt-head.
(i) Test the distance of the bolt from the end of the chamber with gauges .064-inch No. 1 and .074-inch No. 1; the bolt should close over the .064, but not over the .074; when using the latter gauge, light thumb-pressure only should be applied to the knob. Also test to see that the wing of the bolt-head does not lift off the rib of the body.

Firing pin protrusion .040 to .050

A Enfield rifle at the maximum headspace of .074 and a case with a rim thickness of .058 will have .016 head clearance.

Meaning even at the minimum firing pin protrusion of .040 and maximum headspace of .074 the cartridge will fire.

Also I can not believe you do not know how the primer moves to the rear before the case stretches to meet the bolt face.

And the .074 headspace gauge pictured below is very real.

Below are images from a Australian book on accurizing the Enfield rifle.

The images below are in the book above but are from a book published in 1947. The .070 gauge is used in Canada and Australia as commercial NO-GO gauge. "BUT" the .074 gauge is still max military headspace.

And my No.4 Enfield below has two bolt heads fitted.

And I have military Enfield manuals dating to 1929 and pamphlets (pams) back to WWI.

 

[L.Sherm]

I never said you had meant you had a bad number. The question was how can a case grow that much in my case I made a mistake. All I know is the only way I have had .012 case stretch was I was bumping back to far and after 4 or 5 loadings I had a case head separation it's then I checked everything and low and behold it was me using a bad # how I did it I don't know I screwed up. There's something going on with that much stretch whether it's a bad #, or die. I have only had one die I've ever had to have the die touch the shell holder that makes me think your bumping to far going that far and then another 1/4 turn. Turn your die out 3/8 of a turn and try it and compare what do you got to loose

 

[L.Sherm]

Like I said earlier your comparator may not be measuring right on the datum line, stranger things have happened. On a saami 7mm-08 reamer the base to datum line is 1.5998. Not every chamber will be exact. But in a perfect world thats what it's suppose to be shouldn't be to far off that.

 

[bigedp51]

The Hornady cartridge case headspace gauge is not a chamber headspace gauge, it is a comparator gauge. Meaning many cases will not be measured at the exact datum line as a headspace gauge will in the chamber. And as long as you measure a fired case in the Hornady gauge it will tell you how far you have bumped the case shoulder after sizing. And it will be more accurate than using a Wilson type case gauge.

Below a Colt 5.56 Field gauge at 1.4736

Below the same headspace gauge in a adjusted Hornady gauge. A .011 feeler gauge was placed between silver and red sections of the gauge to read the same as the Colt gauge. The average vernier caliper is accurate to .0005 or half a thousands.

Below a fired Lake City 5.56 case from my AR15 in my Hornady gauge, and then the die was set up to bump the shoulder back .003.

The problem is the OP was asking why his cases are longer in over all length after sizing.
And the OP has his shoulder bump down to .001 or .002 and it my understanding his shoulder bump is not the problem.

My English teacher would tell us to "not" write what you are thinking and think about what you are writing.

 

[L.Sherm]

If he's measuring his cases after FL sizing and there one number and he measures them again and there .012 longer there stretching period! Yes it sounds like his dies are squeezing them more than they need to thats why there growing.006 after sizing so its just adding to the problem in any case there stretching you will have case seperation sooner or later you keep using the same brass. I'm done.

 

[jimbires]

timberelk , any chance you live around central Pa ? I'd be more than happy to get together and figure this out . I've got a couple of guys started in reloading , even though I've only been reloading for 41 years . I'm done posting too , it's turned into a ****in contest .

 

[ophious]

Happens all the time from my sizing die. I typically size then trim then tumble. Then sleep with my shiny sexy brass

 

[timberelk]

timberelk , any chance you live around central Pa ? I'd be more than happy to get together and figure this out . I've got a couple of guys started in reloading , even though I've only been reloading for 41 years . I'm done posting too , it's turned into a ****in contest .

Thanks for the offer! Unfortunately I do not, I'm in Utah

 

[J E Custom]

J E CUSTOM

You don't know what you think you know.

Not only did I collect the Enfield rifle I also collected all the military manuals and books on the Enfield rifle. And at one time had the largest Enfield manual sticky in two Enfield forums anywhere on the Internet.

Below are the British headspace gauges and limits directly from the British manual dated 1957.

SM 139- Gauge, Armourer's, headspace, chamber accept, 0.064 inch No1
SM 140- Gauge, Armourer's, headspace, chamber reject, 0.074 inch Royal If bolt closes on SM140--Shant fire!

Below from the British 1931 Instruction for Armourers
4. Action:—Bolt and bolt-head.
(i) Test the distance of the bolt from the end of the chamber with gauges .064-inch No. 1 and .074-inch No. 1; the bolt should close over the .064, but not over the .074; when using the latter gauge, light thumb-pressure only should be applied to the knob. Also test to see that the wing of the bolt-head does not lift off the rib of the body.

Firing pin protrusion .040 to .050

A Enfield rifle at the maximum headspace of .074 and a case with a rim thickness of .058 will have .016 head clearance.

Meaning even at the minimum firing pin protrusion of .040 and maximum headspace of .074 the cartridge will fire.

Also I can not believe you do not know how the primer moves to the rear before the case stretches to meet the bolt face.

And the .074 headspace gauge pictured below is very real.

Below are images from a Australian book on accurizing the Enfield rifle.

The images below are in the book above but are from a book published in 1947. The .070 gauge is used in Canada and Australia as commercial NO-GO gauge. "BUT" the .074 gauge is still max military headspace.

And my No.4 Enfield below has two bolt heads fitted.

And I have military Enfield manuals dating to 1929 and pamphlets (pams) back to WWI.

Ok. I will try one more time and then I will stop trying to help you.

First lets talk about head space.
Head space is measured from the Datum line to the bolt face when using shouldered cases.

Belted cases are measured from the front of the belt to the bolt face.

Rimed cases are measured from the front of the case head to the bolt face.

The gauges you use for the 303 (A rimed case) uses gauges that compare head space from the rim thickness (Front of the rim to the bolt face to make the actual head space .064 to .067 plus the normal 1 to 3 thousandths for the actual head space. So if you inserted the .064 gauge and the bolt would just barely close you would have .0000 head space and would be the minimum SAMME chamber head space.

If the .067 gauge was used and it would barely allow the bolt to close,
you would have .003 thousandths head space Not .067 as you posted.
(The reason I questioned your post for clarification).

The use of the .074 gauge is to let you know that the chamber has .010 thousandths head space, not .074 ) and would be to much head space
and could be dangerous.

These gauges only work if the rim thickness is within specified thickness
that can be added to or taken away from the gauge to end up with the final head space dimension.

Head space is whatever clearance exist between the back of the case head and the bolt face with the cartridge pushed forward against which ever part of the chamber the design is used to locate the case. (Front of rim, front of belt, datum line and the front of the case on rimless cases like the 45 Auto and many other rimless cartridges that uses the case mouth to set the head space.

On the primer issue. The case is not held in place in the chamber if it is full length sized so it will be the first to move when the powder is ignited. the fact that the case is pushed forward sometimes depending on the chamber fit by the firing pin strike , does not mean that the case stays there until the powder starts to burn forcing the primer to move first. The primer IS pressed in place and does not move before the case does and with the case in full contact with the bolt face, the primer will/cannot move.

The only thing that will break the initial primer seal is over pressure loads and this causes bolt face erosion due to high pressure gasses escaping past the primer seal cutting the bolt face. If the primer seal was broken every time A round was fired, the bolt face would not last very long because this seal prevents the gas from channeling through the primer pocket and escaping the cartridge allowing high pressure to cut the bolt face and ruining the case on the first firing.

One other thing. In your moving drawing, you are saying that head space is measured from the end of the breach to the bolt face, this is also false. This clearance called bolt clearance and has nothing to do with head space. what you are calling head clearance in your drawing IS actual head space, and where it is measured.

Just to be sure I had not misinterpreted you post I went back and carefully read them again and you posted clearly stated that all I had thought you claimed, was there.

If this is not clear enough to all, I will make no more attempts to correct your numbers.

Sorry If I offended you or anyone else, but these mistakes needed to be discussed/explained so no one would get into trouble.

J E CUSTOM

 

[bigedp51]

Head space is whatever clearance exist between the back of the case head and the bolt face with the cartridge pushed forward against which ever part of the chamber the design is used to locate the case.

You are wrong again, head clearance is the space between the rear of the case and the bolt face. This is in the SAAMI definitions so why don't you look it up and learn something.

On the primer issue. The case is not held in place in the chamber if it is full length sized so it will be the first to move when the powder is ignited. the fact that the case is pushed forward sometimes depending on the chamber fit by the firing pin strike , does not mean that the case stays there until the powder starts to burn forcing the primer to move first. The primer IS pressed in place and does not move before the case does and with the case in full contact with the bolt face, the primer will/cannot move.

Wrong again, the ejector and or the firing pin will push the case forward until it contacts the chambers shoulder. And if the case was the the first thing to move when the powder is ignited the cases would never stretch because it would be touching the bolt face

The cartridge is pushed forward in the chamber and when fired the soft and thinner upper section of the case expands and grips the chamber walls. Then as the chamber pressure increases and reaches the yield strength of the brass the base of the stretches to meet the bolt face.

And last but not least primer do back out of the primer pocket, and thats why the military crimps the primers in place.

Rifle FAQs
https://www.sierrabullets.com/ask-sierra/faq/index.cfm
Are flattened primers always an indication of high pressure?
Not necessarily. Follow along for a moment. At the cartridge's ignition, a light load won't always fully expand the case within the chamber. It does, however, develop enough pressure to force the primer out of the pocket and against the bolt face, at least as much as headspace will allow. An instant after the primer has been forced back out of the pocket, the pressure will begin to drive the case backwards towards the bolt face. As the case moves back, it reseats the primer, often flattening it in the process. When the case is extracted and examined, the primer will appear to have been used in an extremely high pressure load. In some instances, primers can be a good indication of pressure. In others, they can be extremely misleading and utterly worthless as pressure indicators.

 

[MagnumManiac]

Bigedp51,
Your statement of the case "reaches the yield strength of the brass" is not exactly accurate. If the yield point, which is in fact the failure point, of the brass was reached, it would come apart, swell or flow into places it shouldn't.
The truth is that the brass expands then springs back a thou or two, this is known as it's plastic state, beyond this point, it will expand and stay like it without springing back at all.

I like your posts, but in this instance your terminology is incorrect.
No offence is intended, just steering you in the correct terminology.

Cheers.

 

[DUSTY NOGGIN]

Thanks for the offer! Unfortunately I do not, I'm in Utah

SLC?

 

[J E Custom]

You are wrong again, head clearance is the space between the rear of the case and the bolt face. This is in the SAAMI definitions so why don't you look it up and learn something.



Wrong again, the ejector and or the firing pin will push the case forward until it contacts the chambers shoulder. And if the case was the the first thing to move when the powder is ignited the cases would never stretch because it would be touching the bolt face

The cartridge is pushed forward in the chamber and when fired the soft and thinner upper section of the case expands and grips the chamber walls. Then as the chamber pressure increases and reaches the yield strength of the brass the base of the stretches to meet the bolt face.

And last but not least primer do back out of the primer pocket, and thats why the military crimps the primers in place.

Rifle FAQs
https://www.sierrabullets.com/ask-sierra/faq/index.cfm
Are flattened primers always an indication of high pressure?
Not necessarily. Follow along for a moment. At the cartridge's ignition, a light load won't always fully expand the case within the chamber. It does, however, develop enough pressure to force the primer out of the pocket and against the bolt face, at least as much as headspace will allow. An instant after the primer has been forced back out of the pocket, the pressure will begin to drive the case backwards towards the bolt face. As the case moves back, it reseats the primer, often flattening it in the process. When the case is extracted and examined, the primer will appear to have been used in an extremely high pressure load. In some instances, primers can be a good indication of pressure. In others, they can be extremely misleading and utterly worthless as pressure indicators.

The last drawing is the only one you have shone that is correct. but it does not agree with what you posted time after time.

So you go ahead collecting and I will go on building and everyone will be ok.

THE END

J E CUSTOM