What's "your" favorite way to measure headspace and why?

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MartyK2500

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I am about to purchase a tool to measure headspace.
There are a few design of tools out there, i imagine there is no real need to buy them all.
What do you guys use, and how accurate is it?

From what i see they have GO/NO GO/FIELD gauges in 308 and 7.62
There is this gauge from RCBS that measures a fired casing
And theres a measuring tool that goes inside the chamber and you can see how many thous you got, altough i'm not sure on this one, i might have mistaken troat erosion tools for headspace tools.
 
Depends on what you are doing.
If you are measuring a used rifle to see if it's safe to fire, or installing a barrel and or reaming a short chambered barrel then go/no go/ field gauges.
If you are trying to determine headspace on a rifle you have already fired or one that you know is safe but just want to double check and or wanting to figure out a chambers headspace to set up your reloading dies, then the case gauge is useful.
The case gauge is really handy also in that you don't need to disassemble your bolt to get a decent reading by simply measuring or just checking a fired case.

In rifles with a spring loaded ejector in the bolt face, you will have to disassemble the bolt use the go/no go/ field gauges.
 
I use a set of gauges. Go/no-go/field at the beginning. I have since "stepped up" to a 9 piece 308 head space set and a set of fine (narrow) feeler gauges. The cost is pretty high for a fella planning on assembling a couple rifles..... You can buy 3 pull through readers for about the same cost!

I still use the go/no-go gauges for 30-06 as I don't seem to do that many 30-06 chambers.

The RCBS unit is nice if measuring fired cases on a rifle, but pretty much useless when building a rifle. IMHO.

Cheers!
 
Thanks for the reply.
A re-barrel isn't in the near future, unless Mr Wolverine gets these M14s in quicker than expected

I was under the impression, for a norinco rifle, run a 7.62 field gauge in it, does not close, shoot some 7.62 and run brass in RCBS gauge and i have my headspace. I guess getting the full set of go/no go would make better sense, i see myself fitting a new bolt sooner than later
 
MartyK2500 said:
Thanks for the reply.
A re-barrel isn't in the near future, unless Mr Wolverine gets these M14s in quicker than expected

I was under the impression, for a norinco rifle, run a 7.62 field gauge in it, does not close, shoot some 7.62 and run brass in RCBS gauge and i have my headspace. I guess getting the full set of go/no go would make better sense, i see myself fitting a new bolt sooner than later
Click to expand...

I wouldn't bother with a full gauge set if I was just swapping a bolt on one rifle. A go/no-go and maybe a field should be all that is required.

Cheers!
 
Thanks that what i will do

Get full set of 7.62 go/nogo/field only

I can hardly imagine a norc barrel getting in the 308 range even with a usgi bolt
 
A go gauge with some Plastigauge between the back of the gauge and the bolt face will tell you what the headspace is. You could also cut shim material to fit and stack shims on the back of the gauge using a small amount of grease to stick them on.
 
MartyK2500 said:
Thanks that what i will do

Get full set of 7.62 go/nogo/field only

I can hardly imagine a norc barrel getting in the 308 range even with a usgi bolt
Click to expand...

I currently have a Nork on the bench that headspaced 1.648, swapped a used bolt (Chinese) from the parts bin... After lapping the bolt, 1.632. Very happy with the result.

I have also seen headspace of 1.627 after a USGI bolt was installed. A bit too tight IMHO.
 
MartyK2500 said:
Lol a 3 thou crush on a chinese gun

If you don't mind me asking, what was to be done with this setup to get back to 1.630"?
Click to expand...

Well, there are only really 4 options.....

1- cut the chamber deeper. Not really an option with a chrome lined barrel, unless you want to buy a new reamer.... I'd never trust that reamer again on a $500+ short chambered barrel.
2- swap the barrel for another Chinese one that's in good shape or a USGI or "other" barrel, and re-measure headspace, repeat till you find one that "fits".
3- install a short chambered criterion or Kreiger and cut the proper chamber.
4- leave it see if it'll shoot!

The owner of that firearm opted for #4 but hedged his bet and ordered a criterion from Hirsch Precision (site sponsor). As it turned out the rifle functions just fine! The owner has plans to have the GI contour criterion installed next winter.
 
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Cool info thanks

Having more than one norinco m305 is a good idea then.
Good thing i ordered two to start.
So i can mix and match parts if needed.
 
MartyK2500 said:
I am about to purchase a tool to measure headspace.
There are a few design of tools out there, i imagine there is no real need to buy them all.
What do you guys use, and how accurate is it?

From what i see they have GO/NO GO/FIELD gauges in 308 and 7.62
There is this gauge from RCBS that measures a fired casing
And theres a measuring tool that goes inside the chamber and you can see how many thous you got, altough i'm not sure on this one, i might have mistaken troat erosion tools for headspace tools.
Click to expand...

this is what I do , buy or make a go gauge .
the bolt should close on the go gauge .
put a piece of shim stock 1.5 to 2 thou thick on the back of the go gauge ,the bolt should not close , or just close with force .

if the bolt closes , either continue adding shim stock until the bolt won't close ,

or
put a piece of something compressible , like soft lead wire , plastigauge , or even something like trident gum .
then close the bolt on this and measure the thickness .
 
MartyK2500 said:
Thanks that what i will do

Get full set of 7.62 go/nogo/field only

I can hardly imagine a norc barrel getting in the 308 range even with a usgi bolt
Click to expand...

Put a TRW bolt in mine, and the bolt would just barely close on a SAAMI .308 No Go. I'm fine with that.
 
Cool i never expected a bolt could bring a norc in 308 territory, i guess i was underestimating my chinese rifles, i purchased them mainly for the forged receiver
 
All kinds of good advice here! At the end of the day, the Norinco M305 or whatever is stamped on your reciever is a a battle rifle.

I just built a Criterion barreled 2007 Norinco and finish reamed that chamber until the bolt lug closed. I fired and measured some sample rounds. I ended up with a 2 thou chamber or 2 thou + 1.630" (SAAMI GO gauge). That works for me! :) Some of you at my latest clinics have played with this rifle! :cool:

Cheers: :wave:

Barney
 
Since I build rifles, I prefer a full set of PTG headspace gauges (1.630" to 1.639"). I ream until I achieve 1.632" to 1.633."

I use a GO gage with a Hornady Headspace gauge on a digital caliper. I insert the GO gauge into the headspace gauge and zero the caliper. I then size my brass and it indicates +/- length from GO. In other words, after I zero my calipers on a GO gauge, I measure my sized case and if it reads 0.001", then that means my brass is 0.001" over GO, or 1.631." If it reads -0.002", then it's 0.002" under GO, or 1.628."

Tony.
 
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