shoulder length measuring vs pressure- silly question of the day

[Bart B.]

Last time I estimated, the number of people who think extractors pull case heads back against bolt faces keeping them there until ejecting the fired case, was....... 4,321

 

[dellet]

The shoulder is moved to become part of the case body. The shoulder did not move forward. The new shoulder is formed from part of the neck. With the 8mm57 the case took on the appearance of a 30/06 case with a very short neck.

Had the firing pin drove the case forward to the shoulder of the chamber the case would have the same shoulder it started with and there would be little change to the length of the neck.

F. Guffey

Fixed that for you.

Sounds like you were making what would be an 8mm version of the 7mm maximum or Improved short neck.

 

[fguffey]

The shoulder is moved to become part of the case body.

Thank you for the effort but the shoulder did not move, the shoulder on my case was erased, flattened out and became part of the case body. Years ago I suggested reloader scribe the case body/shoulder juncture before firing. To do that they would have had to remove their hands from their pockets or key boards. The scribed line around the case would become an artifact that would located the position of the shoulder before firing and sizing.

I find it impossible to move a shoulder back with a die that has case body support, all other reloaders calim they bump the shoulder back and they move the shoulder back and they move the shoulder forward. Again; I said I find it impossible to move the shoulder back with a die that has case body support, back to all other reloaders tell me 'daily' they can move the shoulder back and they claim they can bump a shoulder back and they never say 'how?'.

F. Giffey

 

[fguffey]

Sounds like you were making what would be an 8mm version of the 7mm maximum or Improved short neck.

Someone else did an experiment, he increased the length of a 30/06 chamber from the shoulder to the bolt face .060" +? believing he would have case head separation with that much clearance. I do not think he knew what happened when he pulled the trigger but his cases die not suffer case head separation and he did not scribe the case body/shoulder juncture.

I fired 8mm57 ammo in an 8mm06 chamber, if the other guy did not get case head separation with .060: clearance there is no way the case is going to hold together with .227" clearance. Sure enough, I got the same results; no case head separation and my shoulders did not move, they were erased, flattened out and formed to the chamber when they became part of the case body. So my killer firing pins crushed the primers before the case, powder and bullet made it to the front of the chamber?

F. Guffey

I am the fan of cutting down on all that case travel, I form first and then fire. I did nothing to the 8mm57 cases before I chambered them in the 8mm06 chamber. And then one day I asked someone if they would consider someone handed the other shooter the wrong rifle. And then they had to go back to find out what rifle he used in his experiment.

F. Guffey

 

[Eddie Harren]

Someone else did an experiment, he increased the length of a 30/06 chamber from the shoulder to the bolt face .060" +? believing he would have case head separation with that much clearance. I do not think he knew what happened when he pulled the trigger but his cases die not suffer case head separation and he did not scribe the case body/shoulder juncture.

I fired 8mm57 ammo in an 8mm06 chamber, if the other guy did not get case head separation with .060: clearance there is no way the case is going to hold together with .227" clearance. Sure enough, I got the same results; no case head separation and my shoulders did not move, they were erased, flattened out and formed to the chamber when they became part of the case body. So my killer firing pins crushed the primers before the case, powder and bullet made it to the front of the chamber?

F. Guffey

I am the fan of cutting down on all that case travel, I form first and then fire. I did nothing to the 8mm57 cases before I chambered them in the 8mm06 chamber. And then one day I asked someone if they would consider someone handed the other shooter the wrong rifle. And then they had to go back to find out what rifle he used in his experiment.

F. Guffey

More from Prof. Irwin Guffey

 

[fguffey]

Last time I estimated, the number of people who think extractors pull case heads back against bolt faces keeping them there until ejecting the fired case, was....... 4,321

I do not believe you but I will tell you if there were 5 not one of them not could determine if it is possible. If reloaders were no so desperate for attention I believe one of them could determine clearance on either end in thousandths.

F. Guffey

 

[dmoran]

TEAM FGUFFEY​

 

[Bart B.]

I do not believe you but I will tell you if there were 5 not one of them not could determine if it is possible.

What rifle make and model has extractors pulling and holding case heads against bolt faces that withstand 30 pound spring forces driving 3 ounce firing pins into primers at near 10 fps?

 

[dellet]

Thank you for the effort but the shoulder did not move, the shoulder on my case was erased, flattened out and became part of the case body. Years ago I suggested reloader scribe the case body/shoulder juncture before firing. To do that they would have had to remove their hands from their pockets or key boards. The scribed line around the case would become an artifact that would located the position of the shoulder before firing and sizing.

I find it impossible to move a shoulder back with a die that has case body support, all other reloaders calim they bump the shoulder back and they move the shoulder back and they move the shoulder forward. Again; I said I find it impossible to move the shoulder back with a die that has case body support, back to all other reloaders tell me 'daily' they can move the shoulder back and they claim they can bump a shoulder back and they never say 'how?'.

F. Giffey

It is impossible to change the shape of a metallic object without movement of material.

You can argue what that movement is called, bumped, flattened, erased, eradicated or making a ham sandwich. No matter what you call it, your basically multi diameter, cylinder shaped piece of brass, changed shape through movement of material. You can make body out of neck, or neck out of body, but it won't happen without displacement of material.

As far as expecting case head separation, I don't know why you would have expected that. If the firing pin could reach the primer and the chamber was basically the same diameter at the case head body junction, then the case head was fully supported.

I would have been more worried about the shoulder collapsing or having a big dent in it.

Since the 8x57 has more body taper than 8mm-06, the first place the case should grab the chamber is at the rear minimizing stretch in that area and the thinner brass father from the case head should be more likely to stretch and fail.

Using the max powder charge for the 8x57 and firing in a chamber that has probably at least 10% more volume really does not sound all that dangerous. It had room plenty of to expand

Depending on the type of extractor, the biggest trick would be getting the primer close enough to the firing pin to light off. Generally the bolt needs something to push the cartridge against to get the rim past the extractor.

A couple of notes from experience.

You might of had different results if you used a Military primer, it takes a bit more force to fire. So you probably would have moved the cartridge forward out of reach of the firing pin, before hitting the anvil. .010" too much in the distance between the bolt face and shoulder can cause a misfire. This would support the theory that the cartridge moves forward when the pin hits the primer. It is not a light primer strike issue, it's lack of case support.

Cartridge weight alone is enough resistance to fire a 45 acp in a Colt New Service revolver chambered in .45 Colt without the half moon clips.

 

[fguffey]

Depending on the type of extractor, the biggest trick would be getting the primer close enough to the firing pin to light off. Generally the bolt needs something to push the cartridge against to get the rim past the extractor.

Failure to fire was not a problem, reloaders perceive the shoulder of the case being .227" from the shoulder of the chamber would be a problem. There was never a consideration given to the possibility the case would suffer case head separation.

One more time, a smith built 4 ,magnificent rifles, he also made the reamer. The chamber was similar to a 7mmm Gibbs. He had 5 case head separations out of the first 10 rounds fired. He called me: I informed him he could have checked to determine if there was a chance that could happen before he left the shop, I told him I could have met him at the range and 'fixed' the problem long enough for him to form his cases. I told him I could have formed his cases before he fired them.

F. Guffey

 

[Eddie Harren]

"I told him I could have formed his cases before he fired them."

You told me that you could make me the datums you said you would but, you never did. I see it as a case of "all flash and no cash".

 

[dmoran]

fguffey Headspace & Reloading Center

 

[dellet]

Failure to fire was not a problem, reloaders perceive the shoulder of the case being .227" from the shoulder of the chamber would be a problem. There was never a consideration given to the possibility the case would suffer case head separation.

One more time, a smith built 4 ,magnificent rifles, he also made the reamer. The chamber was similar to a 7mmm Gibbs. He had 5 case head separations out of the first 10 rounds fired. He called me: I informed him he could have checked to determine if there was a chance that could happen before he left the shop, I told him I could have met him at the range and 'fixed' the problem long enough for him to form his cases. I told him I could have formed his cases before he fired them.

F. Guffey

That almost sounds like he left the case neck too long knowing it would shorten and pinched the bullet in the neck.

What was his mistake?

 

[pirate ammo]

That almost sounds like he left the case neck too long knowing it would shorten and pinched the bullet in the neck.

What was his mistake?

his mistake,yours,mine, everybody else is trying to get into Guffys mind,impossible,might be a case of no mind,or a case of S.Hawkins mind,case shoulder mind melded into case thanks
to Mr.Spock.one of these days I'm going to build a light saber and be a jedi,and then I will know where all good shoulders go to rest.i the meantime I'm going to shoot pigs and
drink more tequela,,

 

[Dusty Stevens]

Failure to fire was not a problem, reloaders perceive the shoulder of the case being .227" from the shoulder of the chamber would be a problem. There was never a consideration given to the possibility the case would suffer case head separation.

One more time, a smith built 4 ,magnificent rifles, he also made the reamer. The chamber was similar to a 7mmm Gibbs. He had 5 case head separations out of the first 10 rounds fired. He called me: I informed him he could have checked to determine if there was a chance that could happen before he left the shop, I told him I could have met him at the range and 'fixed' the problem long enough for him to form his cases. I told him I could have formed his cases before he fired them.

F. Guffey

So this gunsmith called you for help and the only help you gave him was a coded message about what you woulda done- no help there either?

 

[ClassCat]

So this gunsmith called you for help and the only help you gave him was a coded message about what you woulda done- no help there either?

He used ""THE FORCE""

 

[rebel]

Failure to fire was not a problem, reloaders perceive the shoulder of the case being .227" from the shoulder of the chamber would be a problem. There was never a consideration given to the possibility the case would suffer case head separation.

One more time, a smith built 4 ,magnificent rifles, he also made the reamer. The chamber was similar to a 7mmm Gibbs. He had 5 case head separations out of the first 10 rounds fired. He called me: I informed him he could have checked to determine if there was a chance that could happen before he left the shop, I told him I could have met him at the range and 'fixed' the problem long enough for him to form his cases. I told him I could have formed his cases before he fired them.

F. Guffey

Ok, I gotta throw my hat in this ring. Little different approach. Guffey I had a factory bolt action rifle and a customer of mine had the same model. He kept bringing me a half a box of ammo back with primers hit, not fired. Since I was a reloader, I had only experienced this with hard cup magnum primers until a half a dozen firings, then it would set one off 90% of the time. I took every bit of that ammo in my store and compared it ( measured base to datum ) to brass fired at least 5 times in the rifle. The chamber was longish, the factory ammo was short - so short in fact it would not fire in an AR - 15 ( floating firing pin ). The factory's warranty fix was for me to send the bolt back. Upon receiving it back I (as well as others that had similar issues) I noted that the extractor had been changed. It fixed absolutely nothing.
I know I could jamb a bullet with a handload to hold the case "long" enough to go boom and stretch brass.
What is the other way I could have made the factory ammo fire?
How could I make up for that lack of headspace?
The fact that all cases had hits on the primers, yet did not fire - what is your explanation of that?
I have not had any experience with your theories other than this thread. I'm not making fun of you. I really want to hear your explanation of this particular situation.

 

[WillyTP]

Can’t wait for the popcorn and fireworks.......

 

[fguffey]

That almost sounds like he left the case neck too long knowing it would shorten and pinched the bullet in the neck.

What was his mistake?

dellet, I would like to help you but they will not allow me to type any slower, when I hit the send/post button it all goes out at the same speed. I did not assume there would be a reloader on this forum that did not understand the difference in length between the 30/06 case and the 8mm57 case. The difference in length between the 8mm57 and 8mm06 is .254"; I understand it is a mind boggling thing and as proven by this thread most reloaders can not keep up.

F. Guffey

 

[Lone Hunter]