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SAAMI head space dimensions- 3006 ?
- Thread starter 06shooter
- Start date
I just measured my Hornady gauge and it is at .372 instead of .375 " .
There ya go. Another reason to use your gauge to compare YOUR fired cases to YOUR sized cases and forget what SAAMI says. The gauge is not precise enough to compare to SAAMI and was never intended to do so.
So what do you guys suggest in regards to what brand/ maker of a head space chamber gauge for a hunting rifle ?
"you guys?"
I don't, I do not shoot gages, I shoot ammo. A 30/06 go gage will chamber in every 30/06 chamber I own. That does not give me the good feeling it gives everyone else. I want a chamber length gage? I make one, problem: There are 14 different length between minimum length to field reject gage length.
A go-gage is a standard, it is a transfer and it is a verifying tool. I know, no one understands.
F. Guffey
a go-gage is a standard, it is a transfer and it is a verifying tool. I know, no one understands.
From what I understand, it is used by gunsmiths to verify after a re- barrel job.
[/QUOTE] it is used by gunsmiths to verify after a re- barrel job. [/QUOTE]
The head space gage can be used to verify the length of the chamber, closing the bolt on the gage with resistance to closing is a bad habit. It can be used to verify reloading dies with shell holders. All that is required is a feeler gage, again, some use light. I use the feeler gage because I want to know the answer in thousandths.
Back to the bolt closing on a go-gage, what is the length of the chamber from the shoulder to the bolt face?
F. Guffey
The head space gage can be used to verify the length of the chamber, closing the bolt on the gage with resistance to closing is a bad habit. It can be used to verify reloading dies with shell holders. All that is required is a feeler gage, again, some use light. I use the feeler gage because I want to know the answer in thousandths.
Back to the bolt closing on a go-gage, what is the length of the chamber from the shoulder to the bolt face?
F. Guffey
[Back to the bolt closing on a go-gage, what is the length of the chamber from the shoulder to the bolt face?
Have it casted , a no go on the barrel job is what I should have wrote ]
06Shooter, here's how a 'smith uses .30-06 chamber headspace gauges when rebarrelling;
There's two gauges commonly used; one is the GO (minimum) gauge measures 2.0487" from its head to the shoulder reference, the other's the NO-GO (maximum) gauge that's .010" longer or 2.0587"
The 'smith runs the reamer into the barrel chamber after reaming it to about the correct depth that lets a stripped bolt not close on the NO-GO gauge but will close easily on the GO gauge. If it doesn't close on the GO gauge, he'll ream it a few thousandths deeper, then try again. When that's done, the actual chamber headspace is somewhere between those numbers. Some 'smiths have gauges in .001" increments and when one doesn't let the bolt close on it but another .001" less does, the chamber headspace is somewhere between the two gauge dimensions.
That's the best way to measure actual chamber headspace. Years ago, there were adjustable gauges with a thimble on them graduated in .001" steps. It was set then locked at one dimension then tried in the chamber with a stripped bolt. If the bolt didn't close on it, it was reset to .001" less, then tried again. I used one decades ago I'd borrowed from a 'smith and it was both easy and amazing. My 7.62 NATO Garand's chamber read about 1.6312" as best I could interpolate its thimble adjusted to sub .001" increments.
Most 'smiths like to make chambers close to the GO gauge dimension for best accuracy with new cases and long case life for reloaders.
There's also a .30-06 FIELD (sometimes called FIELD REJECT) gauge that about 2.064" or thereabouts that when used, and the bolt closes on it, the chamber headspace is longer than what's considered safe. Some 'smiths think any chamber headspace dimensioin longer than the NO-GO gauge should not be used.
There's two gauges commonly used; one is the GO (minimum) gauge measures 2.0487" from its head to the shoulder reference, the other's the NO-GO (maximum) gauge that's .010" longer or 2.0587"
The 'smith runs the reamer into the barrel chamber after reaming it to about the correct depth that lets a stripped bolt not close on the NO-GO gauge but will close easily on the GO gauge. If it doesn't close on the GO gauge, he'll ream it a few thousandths deeper, then try again. When that's done, the actual chamber headspace is somewhere between those numbers. Some 'smiths have gauges in .001" increments and when one doesn't let the bolt close on it but another .001" less does, the chamber headspace is somewhere between the two gauge dimensions.
That's the best way to measure actual chamber headspace. Years ago, there were adjustable gauges with a thimble on them graduated in .001" steps. It was set then locked at one dimension then tried in the chamber with a stripped bolt. If the bolt didn't close on it, it was reset to .001" less, then tried again. I used one decades ago I'd borrowed from a 'smith and it was both easy and amazing. My 7.62 NATO Garand's chamber read about 1.6312" as best I could interpolate its thimble adjusted to sub .001" increments.
Most 'smiths like to make chambers close to the GO gauge dimension for best accuracy with new cases and long case life for reloaders.
There's also a .30-06 FIELD (sometimes called FIELD REJECT) gauge that about 2.064" or thereabouts that when used, and the bolt closes on it, the chamber headspace is longer than what's considered safe. Some 'smiths think any chamber headspace dimensioin longer than the NO-GO gauge should not be used.
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No, I don't. Sub MOA accuracy isn't hard to get with most (at least 50% of them) factory rifles shooting their own ammo for a few shots tested properly. Even with chamber headspace near maximum.
They could be anywhere in SAAMI spec range, most likely in the lower range. It needs to be measured if you want good numbers, otherwise compare a fired case + .001" to a GO headspace gauge.
It's unfortunate that everyone testing a given rifle with a given lot of factory ammo will not get the same results.
They could be anywhere in SAAMI spec range, most likely in the lower range. It needs to be measured if you want good numbers, otherwise compare a fired case + .001" to a GO headspace gauge.
It's unfortunate that everyone testing a given rifle with a given lot of factory ammo will not get the same results.
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