Where can I find a set of USGI's for my Garand?  I've checked the usual gun sites and auction sites and didn't turn up anything.  

www.fulton-armory.com

has the 3 gauge kits - GO - NO GO - FIELD (FIELD REJECT) FOR 59.95, BOTH IN 30.06 AND .308

THESE REQUIRE DISCONNECTION OF THE OP-ROD SO YOU CAN HAND WORK THE BOLT IN THE AUTO-LOADING RIFLE.

I DOUBT THEY ARE GI, BUT THEY DON'T NEED TO BE.  TO MY KNOWLEDGE, UNLIKE THE 5.56 X 45 NATO VS .223(SAAMI), AND 7.62 X 51 NATO VS .308 WIN (SAAMI), THERE IS NO SEPARATE MILITARY SET OF STANDARDS FOR 30.06

Check the gage sizes.  M1 minimum (GO) is 1.940" and Maximum (FIELD) is 1.946"

M14 Maximum (FIELD) is 1.6455 and should be correct for a 7.62mm M1 Rifle as well.

There is seriously no need for any gages unless you're just curious or shoot hundreds and hundreds of rounds.  And then you only need the FIELD gage, just like with the M16/AR15.

Cheap gages require the complete disassembly of the bolt.  You headspace by finger pressure, not slamming the action open and shut.

-- Chuck

I don't understand.  Are you saying that you don't have to close the bolt on an M1 or M14 to use a headspace gauge?

And what are the differences between a set of cheap gauges and a set of expensive ones?

Quoted: TO MY KNOWLEDGE[snip]THERE IS NO SEPARATE MILITARY SET OF STANDARDS FOR 30.06

HS gages deal more with the weapon than the caliber. For a Garand one would want Garand gages. Barring that you will need to know the HS dimensions for the weapon then SWAG with SAAMI gages.

M1 HS is
1.940" GO (minimum)
1.946" NOGO (maximum)
1.949" or 1.950" FIELD (reject)
per Scott Duff.

Hatcher lists
1.942" GO
1.944" NOGO
1.946" "overhaul" NOGO
1.950" FIELD

I'm surprised a semi auto would run with HS that tight but it's not a full auto so maybe there is enough slack in the system for it to work.

And this guy omits the NOGO altogether. Dimensions change as errors are discovered.

Worse, Forster lists:
2.049"
2.055"
2.058"

Most likely erroneous. See Forster quote below

JGS sells Garand gages.


There are many kinds of gages, some require disassembly of the bolt (removal of extractor and ejector) to prevent the added tension from giving a false reading. Some gages are relieved for the extractor and ejector and do not require disassembly of the bolt. These gages are sometimes more expensive.

When checking the M1 (or M14) the rifle's op rod and spring are removed leaving just the bolt in the rifle.  Insert the gage and use light finger pressure to see if the bolt closes on the gage.  Don't slam the bolt home.

The proper military gages work without disassembling the bolt.

-- Chuck

When checking the M1 (or M14) the rifle's op rod and spring are removed leaving just the bolt in the rifle.  Insert the gage and use light finger pressure to see if the bolt closes on the gage.  Don't slam the bolt home.

The proper military gages work without disassembling the bolt.  All you really need is the FIELD gage as noted above.

For accuracy or match work:

TB9-1000-237-12 (MATCH QUALITY WEAPONS:  SERVICEABILITY AND MAINTENANCE INSPECTION INFORMATION -- 22 June 1971)) lists 1.946" as Maximum for the M1 Rifle.  Gage number 7319950.  This is the "intermediate" gage noted by Tweak (above) as the "overhaul" NO-GO.

For the M14 the same technical bulletin lists 1.6455", gage 7274790.

-- Chuck

Note on the difference between the Mil HSG and SAAMI (Forster) HSG-----

Both are correct and "read" the same.

The Mil was measured to a reference line intersecting the chamber shoulder angle-----SAAMI is measured to a datum line through the chamber shoulder. Numbers are different but size is the same.

Sorry for jumping on the thread but I checked headspace on a couple of my guns yesterday & noticed a few odd things.

1. 3 colt AR-15 bolts all closed on the NO-Go gauge but not on the field gauge; Is this normal? One has about 3K rounds on the barrel (A 1965 SP1), The others have less than 1K fired.
2. 2 of 3 M1 carbines I checked had the same situation (Closed on NO Go but not on Field)  

I've got an email into Forster, they responded that they would check their numbers and get back to me Monday. The difference is .109" between the GOs. That's more than a minor error in measuring.

garr,

For the AR question go here
ar15.com/forums/announcement.html?b=3&f=66&id=186

Dunno M1 carbines but mil HS is almost always longer, HS is almost always longer in used guns and old guns. In the case of the carbine you're looking at an old, used, military gun. Like I said, HS gages are related more to the weapon than to the calibre.

Quoted: I've got an email into Forster, they responded that they would check their numbers and get back to me Monday. The difference is .109" between the GOs. That's more than a minor error in measuring.

Once again...

Forster's numbers are correct. You cannot compare the numbers from the Mil gauge to the SAAMI because the reference points used for measurment are different.

The Mil was measured to a reference line intersecting the chamber shoulder angle-----SAAMI is measured to a datum line through the chamber shoulder. Numbers are different but size is the same.

If you put a MIL Go gauge (1.940) in a RCBS 30-06 Precision Mic and measure, it will read 2.049

I heard you the first time Noname, excuse me if I don't take what I hear online as gospel.

Nuff said...

Chuck,

I understand the reasons for using headspace gauges, how to use the ones I have (disconnecting and removing the op-rod in order to hand-work the bolt), and why you need only the FIELD for an assembled rife in which the HS is known not to be too short.

I only own one type of HS gauges, they look like the base of a cartridge, have a blunt tip, and don't require bolt disassembly.  

What does a HS gauge that would require bolt dissasembly look like?

h_bakken,

If the gages look like this,



then disassembly of the bolt can prevent incorrect readings.

From your description the above gages are what you have.

Gages as above can be cut to clear the ejector thus allowing the ejector to remain installed.

Gages that don't require bolt disassembly have a rebated rim that does not contact the ejector or extractor.



They are usually "FIELD" gages as that is the environment in which they are intended to be used.

Thanks!

I had ASSUMED that the gauges which I owned did not require bolt disassembly, as no instructions were supplied.  

Why won't the gauge just seat like a cartridge would?  Does the ejector spring force the gauge forward just a little?  

Both my M14 platform rifles were built and headspaced for me already, so I haven't used the gauges 7.62 gauges yet.  I got them from Fulton.

This issue aside, (say I were to always remove the ejector and extractor before using the gauge, regardless of the type of gauge), I am still a little in the dark.  Are there or are there not 2 sets of specifications for 30.06?

I understand that headspace is a firearm-specific measurment.

And where could I order a FIELD gauge with the recessed rim area?

This from Dee at Forster

----- Original Message ----- From: "Rodger Young" <[email protected]> To: "Forster Products" <[email protected]> Sent: Monday, March 08, 2004 11:34 PM Subject: Re: errata > I have been told by another that Forster measures > to a different location than the military did or > something to that effect. Yes, the old ordnance markings are measured from a different datum point.  We decided to be "consistent" about ten years ago and list only S.A.A.M.I. headspace lengths. Note: The old ordnance markings (1.940, 1.946, 1.950) do match up to our S.A.A.M.I. gages in actual headspace lengths.

Anyone with comments on my last reply?

Tweak?

Chuck?