How to accurately measure (not validate) headspace?

fguffey

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4 pages....didn’t read them all, but a GO gauge + plastigage should be a way to get the exact number.

Make sense?
"A way?", yes and then there is understanding what is going on when using plastigage.

F. Guffey
 

nksmfamjp

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"A way?", yes and then there is understanding what is going on when using plastigage.

F. Guffey
C’mon Guffey! Don’t give it to us in riddles.....tell us what you are talking about plastigage crushes when you close the bolt. It comes with a chart to read it. Add that to what you get off your comparator....write it down....its s absolute as you can get!
 

atblis

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I've always wanted to make an adjustable headspace gauge. Basically take a regular gauge split into two halves and add a threaded rod connecting the two halves. You'd then have body sections for the middle that you can swap in and out to get different lengths. Basically accomplishes the same thing as the Forester match headspace gauge set but at a much lower cost.
 

fguffey

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I've always wanted to make an adjustable headspace gauge.
It is possible, it is not a problem but the ones I have used have a problem turning when the bolt is closed so some kind of a friction devise is necessary. I have 5 very small Starrett inside micrometers that are designed to be installed/fixed on one end and adjustable on the other. It would be easy to modify the micrometer.

And then there are many ways to check the length of a chamber but no matter where I go there are those that insist it can not be done.

Again, I have a 3 grinders, 2 wet and one dry. There is nothing I can do about it but I can grind pilots, long tappers, angles and as if that is not enough the grinder will grind to length. If I could get someone to think about it gages can be made on all three grinders. Head space (length of the chamber) can be checked at least three different ways without a head space gage.

F. Guffey
 

fguffey

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.its s absolute as you can get!
write it down....it's as absolute as you can get!
I was thinking there is a remote chance there are reloaders that that are not members of the choir. I was thinking it would be helpful to understand when a head space gage is used when checking the length of the chamber from the shoulder to the bolt face in the perfect world the head space gage is a snug fit. And I believe it helps to understand the case when full length sized or is minimum length the clearance is included in the head space gage. The clearance for a 30/06 is .005".

If the OP used a fired case when using plastigage there would be little to no clearance. I understand that means nothing to you but if a member is not a member of the choir he would understand the go-gage was not necessary.

And if he developed good habits and learned to measure before and again after he would know the length of the chamber.

And he needs to learn the difference in actions, it is possible to determine if the case stretched and or formed. Stretched is the scary one. I will let you expalin that one.

F. Guffey

 

atblis

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It is possible, it is not a problem but the ones I have used have a problem turning when the bolt is closed so some kind of a friction devise is necessary....snip
I don't think that would be a problem with what I am proposing. These wouldn't be adjustable like a micrometer. Effectively it's a fixed gauge that you can adjust to different lengths. I was thinking you could take an existing gauge, drill and tap it along the long axis. Then slice it in the middle. You can add shims in the middle as needed for different lengths.
 
Last edited:

fguffey

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I don't think that would be a problem with what I am proposing.
Forgive, I have offered to modify go gages to go-to infinity gages, that would be a gage that measured the length of the chamber from the shoulder to the bolt face from go-gage length to infinity; problem, no one has a clue what that would be.

Let me know, keep me posted. And there are two ways it can be done.

F. Guffey
 

25WSM

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I still fail to see the point in knowing exactly what your headspace is. I don't give a hoot what length it is as long as it's in the middle somewhere between the go and no-go. It absolutely doesn't mater. It's in spec and safe. And setting up the sizing die can easily be done from fired brass. There is a reason the exact chamber length is not stamped on every barrel. Because nobody gives a crap. It's stamped with the cartridge name and will be no more than .005 to .006 from shortest to longest chamber size for that cartridge. Go ask 100 benchrest shooters how long their chamber is. Most will say minimum spec but will have no clue what the number is. Why. Because they don't give a crap either.
It's a number used to make the reamer and headspace guages from. For everything else it's useless. If your chamber is not in spec is the only time you would want to know how much out of spec it is.
Shep
 

fguffey

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I still fail to see the point in knowing exactly what your head space is. I don't give a hoot what length it is as long as it's in the middle somewhere between the go and no-go.
25WSM, it is OK, no one is insisting your learn to measure the length of the chamber, I doubt there is a member on this forum that would hold it against you if you do not know how.

Though job: When I find people that do not care the most difficult job in the world (for me) is trying to motivate them to care. There are members on this forum that have expressed an interest in knowing how, I believe they have a right to know and I will do nothing to discourage them.

And forgive, the next time I will ask you what you think.

F. Guffey
 

atblis

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I've been wondering if the adjustable gauge thing would be handy for setting up your dies. Maybe measure your chamber with the gauge, then take maybe 0.001" worth of shims out of the gauge and use that to setup your dies. I've never tried to see if the head-space gauges will easy fit into a sizing die. Just a thought. Might be pointless.
 

25WSM

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Well quit telling everyone how you can do it a million and one ways and tell them how to do it. As for me I really don't feel it's necessary to know the exact length. I have no use for that number. That's why the industry uses headspace guages. Sammi doesn't tell you to cut a chamber to an exact number they tell you to cut a chamber to fit a go and not to fit a no-go. Even if you did know this length to the datum point how would someone at home compare their brass to it. You would have to have inserts made with the exact diameter of the datum point and that would get costly. Maybe Hornady missed the boat with their measuring system. Now they need to come out with inerts that match every cartridges datum diameter. That will give you a more informed datum length that they will then bump back how much they like to from that number. But it would be the same setback they would have gotten from reading anywhere else on the shoulder. So to enlighten me to why I need to know my exact chamber length. What do I do with that number. How does it help me to know that number. This is a site we learn from I'm listening. You just haven't told us anything yet.
Shep
 

25WSM

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I like the idea of you adjustable guage. Maybe it can be made with clicks like the whidden dies. You could make it fit your chamber then just dial back a few clicks and put it in your press and screw the did down to touch it and you would be super close. Patent your idea it might be the next big thing.
Shep
 

fguffey

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I've been wondering if the adjustable gauge thing would be handy for setting up your dies. Maybe measure your chamber with the gauge, then take maybe 0.001" worth of shims out of the gauge and use that to setup your dies. I've never tried to see if the head-space gauges will easy fit into a sizing die. Just a thought. Might be pointless.
A head space gage will fit inside of a sizing die. There are a few reloaders than can verify a die with a head space gage. Again, it is not necessary to use shims on a gage in a chamber. It helps if the reloader can verify the gage.

F. Guffey
 

fguffey

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Maybe Hornady missed the boat with their measuring system.
Yes they did, the problem is with reloaders, they wooo and ahhhhh and try to impress each other. In the beginning I said the Hornady tool was a compactor, reloaders insisted the tool was a head space gager. I knew the case does not have head space because SAAMI does not list case head space. Back to Hornady/Sinclair tool. I said the tool was a compactor because the datum had a radius, again, I make datums, my datus have very sharp edges, the sharp edge makes the datum case unfriendly.

The Wilson case gage: The Wilson case gage is a datum based tool, The datum on the Wilson case gage has a radius but when it comes to making tools Wilson knows what they are doing. I believe there are reloaders that have continued to call the Hornady tool a head space gage because they believe the case has head space.

F. Guffey
 

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