AR15.Com Archives
 Where to find a NATO 7.61x51 NATO headspace gauge?
ArmaLiteM15KevinZ  [Member]
2/20/2009 3:35:05 AM
I have a Norinco M14 that I'd like to check the headspace on. I've always heard to use a NATO-spec 7.62x51 gauge to check it. Anyone have an idea where I can find one? Maybe a go/no go gauge? Thanks
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MK262  [Member]
2/20/2009 5:21:17 AM
http://www.brownells.com/aspx/NS/store/ProductDetail.aspx?p=19385&title=.30%20CALIBER%20RIFLE%20HEADSPACE%20GAUGES
1811GNR  [Team Member]
2/20/2009 11:08:48 PM
Those aren't 7.62 gauges. Forster offers their version of NATO gauges but I believe their max is too long @ 1.6455. That is the size for the gauge measuring with a test bolt to determine receiver serviceability. 7.62 NATO max should be 1.6405. Forster or Clymer should be able to make one that length, special order of course. Another option would be a .308 field gauge with a disk of 0.0025" shim stock.
YoteSlayer69  [Member]
2/20/2009 11:44:27 PM
Yopu have to visit diffrant's web site gget the spec's and special order the gauge's you want from Clymer's. thats what i did
lapster  [Team Member]
2/21/2009 12:54:32 AM
Originally Posted By ArmaLiteM15KevinZ:
I have a Norinco M14 that I'd like to check the headspace on. I've always heard to use a NATO-spec 7.62x51 gauge to check it. Anyone have an idea where I can find one? Maybe a go/no go gauge? Thanks


Scott Duff used to have a great set....quality shit but you had to pay for it. I've been looking all over for mine..I might have loan them out...if thats the case, ask scott if he'll give a quantity discount, I'm gonna need more!
http://www.scott-duff.com/
gman556  [Team Member]
2/21/2009 1:29:59 PM
Look at Numerich gun parts

He has Foster 7.62 nato guages there.
LARRYG  [Team Member]
2/21/2009 8:21:38 PM
CMP has GO and NO-GO gauges for 7.62x51.

GO GAUGE

NO-GO GAUGE

It's where I got mine.
LARRYG  [Team Member]
2/21/2009 8:24:40 PM


Hell, those people call them the same:

.308 (7.62 Nato) Match Gauge, 1.630" GO



.308 (7.62 Nato) Match Gauge, 1.634" NO-GO


They are most assuredly NOT the same.

leid  [Team Member]
2/22/2009 1:36:30 PM
The USGI MAX ALLOWABLE 7.62MM & 5.56MM gages shown below are used to determine if the headspace on a rack grade M14 or M16 rifle is safe. They are the gages I use most for checking that a rack grade M14 & M16 rifle is safe to fire; accuracy is another question altogether. USGI 7.62MM & 5.56MM gages have much more generous dimensions than commercial .308 & .223 SAAMI gages. The USGI FIELD gage will give you no warning that your rifle's headspace is approaching the unserviceable REJECT dimension because it is a PASS/FAIL (SAFE/UNSAFE) gage. If a rifle passes a MAX ALLOWABLE gage, there should be no problem using the rifle for an extended period using appropriate mil-spec ammunition. IIRC, the military checks rack grade rifles with an appropriate MAX ALLOWABLE gage once a year. And unlike most commercial gages, the USGI M14 & M16 gages shown do not require the extractor/ejector to be removed to get an accurate reading. Match conditioned M14 & M16 type rifles normally have much tighter headspace than these USGI MAX ALLOWABLE gages were intended to measure.

LARRYG  [Team Member]
2/22/2009 2:06:00 PM
Originally Posted By leid:
The USGI MAX ALLOWABLE 7.62MM & 5.56MM gages shown below are used to determine if the headspace on a rack grade M14 or M16 rifle is safe. They are the gages I use most for checking that a rack grade M14 & M16 rifle is safe to fire; accuracy is another question altogether. USGI 7.62MM & 5.56MM gages have much more generous dimensions than commercial .308 & .223 SAAMI gages. The USGI FIELD gage will give you no warning that your rifle's headspace is approaching the unserviceable REJECT dimension because it is a PASS/FAIL (SAFE/UNSAFE) gage. If a rifle passes a MAX ALLOWABLE gage, there should be no problem using the rifle for an extended period using appropriate mil-spec ammunition. IIRC, the military checks rack grade rifles with an appropriate MAX ALLOWABLE gage once a year. And unlike most commercial gages, the USGI M14 & M16 gages shown do not require the extractor/ejector to be removed to get an accurate reading. Match conditioned M14 & M16 type rifles normally have much tighter headspace than these USGI MAX ALLOWABLE gages were intended to measure.

http://i9.photobucket.com/albums/a72/leid/M14/M14M16USGIGages.jpg


Where can I get those? It is a pain removing the firing pin to check every time.

leid  [Team Member]
2/22/2009 2:16:52 PM
Larry,
Bring your commercial gages and some really good beer to your master machinist buddy and turn him loose on 'em. For quality assurance, don't let him suck down any brewski until he is finished turning the ends of your gages down.
I sold the last of my spare USGI headspace gages last year and have no source for any more USGI M14 gages at present. But Bill Ricca did have the USGI M16 gage pictured for sale (NIW) . I have no connection with him.


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