Shoulder Gage to Measure Head Space

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Trevor60

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Would any one know who makes or sells shoulder gages? I would like to measure the head space in order to determine the amount of shoulder bump I am getting. I would prefer not to purchase the RCBS precision mic. Looking for a .308 gage.

Much appreciated
Trevor
 
Headspace is checked, not measured, with headspace guages. Brownell's sells 'em. Cartridges do not have headspace. Headspace is a rifle manufacturing tolerance that allows ammunition from all makers to be used in all like chambered rifles.
 
When you have a rifle fitted with a precision barrel and chamber, the smith can make you an exact copy of the chamber (shoulder, neck and throat) and you can use this little barrel stub to compare brass length before and after firing and/or sizing.
 
Thanks Sunray. I believe i am not explaining myself properly. What i am attempting to do is find out how far i am "pushing" the shoulder back. I have copied and pasted someone elses explaination for better clarification. I believe Guntech is correct except I do not have a chamber stub or GISMO.

While it is best done with the chambering reamer used in your rifle, anything made from a reamer having the same specifications will work. The reamer is run into a piece of steel far enough to cut a little past the body/shoulder junction. It is faced off here, and at a point beyond where the freebore starts. These cutoffs must be true. Put a deprimed, fired case in the thingy (case headspace gauge), and using a caliper, measure from the base of the case to the end of the gauge. Do the same with a sized case. The resized case should measure about .001 less than the fired case.

Mike Ratigan's book indicates that the headspace should be pushed back only about .0005. see pages 100 and 101 for description and picture of thh shoulder gage.

Secondly, a true headspace gauge for cases must have the body/shoulder junction. Most of the time this junction is what gets "moved" for easy chambering, particularly on cases with a generous shoulder angle. For example, if you look at a sized Ackley Improved case, the body/shoulder junction will be a tiny bit rounded. I do mean "tiny." But anyway, a gauge made this way will correctly measure the case headspace.
 
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Stoney Point makes a gauge that measures the datum line midpoint on the shoulder of a fired case. The have a base & ring arrangement that clamps to a regular digital caliper, the ring rests on the shoulder. It works well, but when I use mine I would have difficulty measuring as accurately as you want, 0.0005 is pretty precise! they are sold by Wholesale Sports.
 
Headspace guages do not measure anything. They only test for tolerance. None of them are a copy of the case. They're just a precisely ground piece of steel that is of a specific length. A .308 headspace guage is just such a beastie.
No case from any manufacturer is made precisely enough to be used as a guage or template for any tool.
Guages in general don't measure anything. They're not like dial indicators or micrometer that can give you a number.
"....0005..." That is 5/10,000". Measuring anything that small requires special measuring tools. Regular micrometers measure in thousands of an inch.
In any case, you're letting reloading be far more complicated than it is.
 
In the absence of the little stub that Dennis mentionned, I don't know of any tools other than the RCBS or Stoney Point that would enable you to obtain the measurement that you are looking for.
I suppose that most reloaders just bump the shoulder until cases chamber freely, rather than seek an actual measurement.
 
Sometimes you can use the bullet seating die to compare the amount you bump a shoulder back... if the case is loose going in and out of the die you should get an accurate measurement... just measure how much is out of the die before bumping the shoulder and again after...
 
You can actually measure headspace with a GO gauge if you have a dial indicator. I do this when I have a GO gauge but not a NO-GO gauge......Chamber the GO gauge with a stripped bolt and put a dial indicator on the end of the bolt...the amount the bolt will move fore and aft with the GO gauge in the chamber is the amount of headspace above the minimum.
I installed a factory 6mm barrel into a 700 action a few weeks ago using this method..I had only .0005 bolt movement with the GO gauge in the chamber..and .002 movement on a factory round...
 
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I was able to find usable pictures of the item i was talking about. Some people call it a
"measuring collar"
Here is hoping the images work. all it is a a brass collar cut to the size of a case neck and shoulder (in my case looking for .308) but can be made for any round

harrellsdiex140.jpg


harrellsdiex350.jpg


Now I hope the pictures provide a better understanding of what i am looking for. Would anyone one know where in Canada i might be able to get this or have them made.

Trevor
 
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