Where's Case Head When Round Fires?

[Reloadron]

cw308:

From reading the posts , Ron's chamber measurements for his 308 and sizing to no more then .002 case headspace is exactly what mine is . The question of forward case movement would be .002 as long as the extractor allows. Where is this going and does it matter in any way.

That's my point, things (the case) can only go so fr forward, even if it does go forward while being held by the extractor. If there is anything else to be garnered or learned it escapes me right now.

Ron

[Metal god]

If there is anything else to be garnered or learned it escapes me right now.

Based on the OP and poll . My guess is this is simply the question does the case stay forward or does it slide back to the bolt face when fired . Meaning the case shoulder stays up against the chambers shoulder because the case walls are stuck to the chamber walls not allowing to move rearward or does the case move forward when the firing pin hits it then is immediately forced rearward back against the bolt face do to what ever one thinks causes it to .

As the poll suggest EDIT ( just looked at the poll , only 30% or so beleave differently then the others rather then half ) . That in it's self makes the conversation interesting to me at least . We all can't be right but some of us have done test that seem to show one thing and base there conclusions on that . Not sure what the others are basing there reasoning on ?

How do they say YMMV

[F. Guffey]

From reading the posts , Ron's chamber measurements for his 308 and sizing to no more then .002 case headspace is exactly what mine is

I have asked' "Where did that .002" come from?".

My cases do not have head space and ever tool I use is not a head space gage. Some reloaders have a digital head space gage that looks just like my dial indicator stands. I have clearance; I off set the length of the chamber with the length of the case from the shoulder to the case head.

So I would say he is reducing the length of the case .002" to off set the length of the chamber.

F. Guffey

[Metal god]

Here is another lovely cut chamber . I just shot these from a new PA-10 upper I got on Tues . As you can see the pressure is high enough in the chamber to imprint the poor chamber cut onto the case walls . If it can do that it can hold the case forward as well .



FWIW the upper ran just fine but appears to be really hard on brass . I'm going to do a full review thread on this upper in the near future .

[F. Guffey]

How do they say YMMV

I would say there are reloaders spending too much time making this stuff up. AND there are reloaders that choose to ignore logic and or common sense. And to think this got started with an illustrated cartoon.

F. Guffey

[F. Guffey]

Here is another lovely cut chamber . I just shot these from a new PA-10 upper I got on Tues . As you can see the pressure is high enough in the chamber to imprint the poor chamber cut onto the case walls . If it can do that it can hold the case forward as well

It sounds like you just made that up. I am the fan of 100% contact, 100% contact has more case hold that all of the cross hatching in the world.

F. Guffey

[F. Guffey]

And then there is the shoulder of the case: Someone is going to have to think.

I say it is impossible to bump the shoulder back, I say it is impossible to move the shoulder back with a die that has full length contact with the case. I should not have to explain 'what it is' you need to think about;

[zeke]

https://www.youtube.com/watch?v=w_yN0SESbTA

For whatever it may be worth. Am gonna quess differing physical dimensions/characteristics of chamber/case and differing pressures may produce differing results.

Way beyond me, but appears minimal headspace may be a good thing.

[Metal god]

See 35seconds into the video



LMAO , somewhere Guffey's head is exploding lol

Also see 2min in , did he just say CARTRIDGE HEADSPACE ? ROTFLMAO



Got to love these companies confusing all the new reloaders out there . haha .

I wonder at what point the select few will abandon there tyrannical obsession about what headspace is and can only be ?

[Bart B.]

It would help everyone if we all used the same definition of headspce (head space) in each of the three applicable areas' context; chamber, cartridge and gauges

Regarding the case, I have often thought "body space" well defines the head to shoulder dimension. But I am not going there. Someone once suggested case head to shoulder be called "power space" being back of primer to front of powder charge.

[Bart B.]

Originally Posted by Reloadron

Well you got me on that? I no longer have access to the tools I would need to get that dope.

Ron

Do you have a caliper that measures to thousandths of an inch? And a cleaning rod?

This is all you need plus tools to detail strip the rifle bolt and cut a case in half.

[HiBC]

When? I am conserved about after. How long will it take for them to forget where the information came from? At one time I did not care.

And so now what will you be remembered for? Or just forgotten?


Nobody gets out of here alive. I'm happy to pass on,give away everything I've learned.

If I notice someone else using it....that means what I gave was Gold.


What good does it do me to die with it ?


That would be a true waste of my life

[cw308]

MG
Great pictures , did make me laugh . Well Done
PS: May change my post name to c headspace w 308
Some words just drive people crazy .

Chris

[F. Guffey]

Is the shoulder on a 308 Win case made by full length sizing a 30-06 case in a 308 die, then trimming to 2.010" long, on its neck?
__________________

there are many reloaders in the claims department that claim they use the full length sizing 308W die.

I don't; I have 16 case forming dies, my favorite forming die is the 308 W forming die because it is short. the second most favorite forming die is the 243W forming die because it is short.

I use the 308W forming die (also know as the 308W trim die), the 308W case is close to being .014" larger in diameter at the case body shoulder juncture than the 30/06 case at the same distance from the case head.

there is a chance the case body/shoulder juncture will require fireforming for the case to conform to the chamber.

When trimming 30/06 to 308 I start with the hack saw and finish with a file. rational; when trimming it is necessary to trim close to .100" from each cases, when forming 100 cases that is a lot of trimming.

F. Guffey

[F. Guffey]

After forming with a forming die it is necessary to size the case with a full length sizing die. For those that can keep up with the length of the chamber from the shoulder to the bolt face the reloader can off set the length of the chamber with the length of the case from the shoulder to the case head.

Again, I have a 30/06 chamber that is .016" longer than a minimum length chamber. I adjust the fie off the shell holder .014" when sizing 280 Remington cases to 30/06 cases for that chamber. When finished I have the magic .002" clearance. With the M1917 it is not necessary to use 280 Remington cases; but there is a problem when using 30/06 cases. The 30/06 cases shorten when the case fills the chamber. That is not a problem for anyone else but I am the fan of bullet hold, I want all the bullet hold I can get; that is something I can not do with short neck cases.

F. Guffey

[Reloadron]

Bart B:

Do you have a caliper that measures to thousandths of an inch? And a cleaning rod?

This is all you need plus tools to detail strip the rifle bolt and cut a case in half.

Yes, several times over. So what exactly am I doing and how exactly am I doing it?

Ron

[F. Guffey]

Yes, several times over. So what exactly am I doing and how exactly am I doing it?

You would have had to put a little thought into the idea back when I said I can modify a go-gage into a go-gage that measures to infinity. The owner of the gages was not interested because the gage would no longer be 'period correct'; and he had no interest in going beyond a resource person.

F. Guffey

[Unclenick]

CW308,

Don't worry. SAAMI didn't die and anoint Hornady head of firearms terminology. Hornady bought branding rights to that tool from Stoney Point about 15 years ago or so. From the '90's through that change in branding, Stoney Point (the inventor) sold it as The Head 'N Shoulders Cartridge Headspace Gauge, meaning you could discover your chamber headspace by measuring a case fireformed in it. Cartridge Headspace is a term meaning the amount of headspace in the chamber to accommodate a cartridge. It is a chamber property and not a case property. But when Hornady bought the tool branding rights they changed the name and, as far as I know, were the first to start speaking of "case headspace" as a case property. It still causes confusion today.

[F. Guffey]

And then came L. Willis with his digital head space gage, reloaders did not know the difference, the digital head space gage was a dial indicator stand and at best if could be used as a comparator.

Reloaders never understood the search engine; when a reloader searched for head space gage the first thing came up was digital head space gage. At the time there could not have been more than three reloaders that knew where all of this was headed if reloaders did not stop making this stuff up.

They had a bad habit of polarizing; and nothing has happened to change that.

F. Guffey

[Reloadron]

F. Guffey:

You would have had to put a little thought into the idea back when I said I can modify a go-gage into a go-gage that measures to infinity. The owner of the gages was not interested because the gage would no longer be 'period correct'; and he had no interest in going beyond a resource person.

So exactly how would you do that since you mentioned it a few times?

If I have a known Go gauge I would use a hole punch and maybe punch out a few pieces of maybe stainless steel shim stock. Using a Q-Tip (cotton swab) I would place a tiny dab of a grease on the head of my Go gauge. This will allow my small circular pieces of shim stock to stick to my Go gauge head. Then I would just add the shim stock thickness, which I can check with a micrometer, to my Go gauge dimension.

So how would you do it?

Anyway, that question was directed at Bart and if I knew how to do it with what he mentions I would not have asked.

Ron

[Metal god]

as far as I know, were the first to start speaking of "case headspace" as a case property. It still causes confusion today.

Why is it confusing ? Is it because they used the term or because some refuse to except it ? Simply stating something does not in it self make it confusing .

How many times over the years has it been said that the lord ( Mr guff---err SAAMI ) does not have a name for the measurement on a bottle neck case from head to datum point on a given case ? As we all know this is in fact a VERY important measurement for many of us . If SAAMI refuses to give it a name , then the industry and reloaders will .

Since the beginning of the spoken and written word . When there was no word to describe something ( as the lord has refused to do here ) . The community chose as a whole through dialog over time what will be excepted as the new word and term for said undescribed thing trying to be described , this is no different . It's that simple and you all can not put the tooth paste back in the tube . Why is that so hard to understand and except ? It's not like the dictionary started out with as many words as it has in it's current form .

[F. Guffey]

F. Guffey:

Quote:
You would have had to put a little thought into the idea back when I said I can modify a go-gage into a go-gage that measures to infinity. The owner of the gages was not interested because the gage would no longer be 'period correct'; and he had no interest in going beyond a resource person.

So exactly how would you do that since you mentioned it a few times?

If I have a known Go gauge I would use a hole punch and maybe punch out a few pieces of maybe stainless steel shim stock. Using a Q-Tip (cotton swab) I would place a tiny dab of a grease on the head of my Go gauge. This will allow my small circular pieces of shim stock to stick to my Go gauge head. Then I would just add the shim stock thickness, which I can check with a micrometer, to my Go gauge dimension.

So how would you do it?

Anyway, that question was directed at Bart and if I knew how to do it with what he mentions I would not have asked.

Ron

Ron,

Anyway, that question was directed at Bart and if I knew how to do it with what he mentions I would not have asked.

I know, and I am of the opinion Bart B. is repeating something he heard some bench resters repeating what they heard. Many times I have said I am the fan of transfers; and then I take a lot of time explaining (what seems complicated) how I transfer one dimension from one place to another. And for my efforts I get a lot of' "I am co confused" and after that someone breaks into the routine Bart B. suggested with the cleaning rod.

In my efforts I have never had a member offer to improve on my method and or technique. The first responses I expect are from members that do not believe it can be done or they go into auto response with a long list of tools required. there are not many tools I do not have. That does not mean the tools are required.

One more time: I am the fan of the datum. Problem with discussing datums with reloaders; it brings out the silly in them.

F. Guffey

[tangolima]

Originally Posted by Metal god

..measurement on a bottle neck case from head to datum point on a given case ? As we all know this is in fact a VERY important measurement for many of us .

It is only important if you are manufacturing ammunition to meet saami specs. I don't care whether that measurement is 2.356" or 2.359" as I size brass for one rifle. What I care is the head clearance not to exceed certain amount. I interchange head clearance with head space in all occasions. There has never had any issues or confusion, as the context always clarifies the meaning. The only exception is on this forum. I bend my feeble mind to follow the convention here. It is clumsy at times but not that bad. Reminds me the way I talked to my kids when they were little. They thought I was driving a choo choo everyday when I told them I was an engineer.

-TL

Sent from my SM-G930T using Tapatalk

[Bart B.]

Originally Posted by tangolima

I interchange head clearance with head space in all occasions. There has never had any issues or confusion, as the context always clarifies the meaning. The only exception is on this forum.

SAAMI's glossary explains the difference.

HEAD CLEARANCE
The distance between the head of a fully seated cartridge or shell and the face of the breech bolt when the action is in the closed position. Commonly confused with headspace.

HEADSPACE
The distance from the face of the closed breech of a firearm to the surface in the chamber on which the cartridge case seats. 1. BELT: A type of chamber design in which the cartridge seats in the chamber on an enlarged band ahead of the extractor groove of the cartridge body. 2. MOUTH: A type of chamber design in which the cartridge seats in the chamber on the mouth of the cartridge case. 3. RIMLESS: A type of chamber design in which the cartridge seats in the chamber on the shoulder of the cartridge case. 4. RIMMED: A type of chamber design in which the cartridge seats in the chamber on the rim or flange of the cartridge case.

Look at Sinclair's video link posted earlier to see what they call headspace.

[Bart B.]

Originally Posted by Reloadron

Bart B:


Yes, several times over. So what exactly am I doing and how exactly am I doing it?

Ron

1. Remove the rifle bolt then take it apart completely.

2. Cut a 308 case in half then full length size the back half. Put a primer in it.

3. Put the stripped bolt back in the rifle chambering that half case.

4. Put the cleaning rod into the barrel muzzle then stand the rifle muzzle up.

5. Put the firing pin in the bolt then measure how far you can move the pin and case up and down in the chamber.

6. Put just the extractor and pin back in the bolt, chamber the case then measure again.

What are the measurements? What does the difference tell you.