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Discussion Starter #1
Armscorp receiver built with all USGI parts. Was told it was headspaced, an it will close on the no go but not on the Field gauge, common for military rifles. Does this sound correct or should I have concerns....MW is 0, so sounds like a pretty new barrel was installed.
 

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GO: Corresponds to the minimum chamber dimensions. If a rifle closes on a GO gage, the chamber will accept ammunition that is made to SAAMI’s maximum specifications. The GO gage is essential for checking a newly-reamed chamber in order to ensure a tight, accurate and safe chamber that will accept SAAMI maximum ammo. Although the GO gage is necessary for a gunsmith or armorer, it usually has fewer applications for the collector or surplus firearms purchaser.
NO-GO: Corresponds to the maximum headspace recommended for gunsmiths chambering new firearms. This is NOT a SAAMI-maximum measurement. If a rifle closes on a NO-GO gage, it may still be within SAAMI specifications or it may have excessive headspace. To determine if there is excessive headspace, the chamber should then be checked with a FIELD gage. The NO-GO gage is essential for checking a newly-reamed chamber in order to ensure a tight and accurate chamber.
FIELD: Corresponds to the longest safe headspace. If a rifle closes on a FIELD gage, its chamber is dangerously close to, or longer than, SAAMI’s specified maximum chamber size. If chamber headspace is excessive, the gun should be taken out of service until it has been inspected and repaired by a competent gunsmith. FIELD gages are slightly shorter than the SAAMI maximum in order to give a small safety margin.
 

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Armscorp receiver built with all USGI parts. Was told it was headspaced, an it will close on the no go but not on the Field gauge, common for military rifles. Does this sound correct or should I have concerns....MW is 0, so sounds like a pretty new barrel was installed.
You say your gun is all USGI parts, does this include the barrel? If it has a non altered USGI barrel, the HS will be longer than a SAAMI spec .308 bbl.. Normally a USGI chambered barrel will "swallow" the go and no-go SAAMI gages. Search the threads here on TFL to understand the difference in chamber lengths. dozier
 

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Depends on the of gauges you are using. NATO 7.62 chamber or .308 commercial...

If its a NATO 7.62 chamber, it likely will close a commercial .308 no-go gauge.

If you have a real GI ordinance gauge, and its a NATO 7.62 chamber, your bolt should NOT close on it. If it does, your headspace is too long and should be fixed.

BTW, the numbers on a throat erosion gauge don't really mean anything by themselves. TE gauges can only be used, reliably, as a progressive wear gauge...

A good TE gauge can show a whole range of different readings on different barrels and makes of barrels that have no wear whatsoever. Use it as progressive wear gauge only. Meaning, take a reading and that's your starting reference. As you shoot, measure the wear from that reference...
 

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Discussion Starter #7
You say your gun is all USGI parts, does this include the barrel? If it has a non altered USGI barrel, the HS will be longer than a SAAMI spec .308 bbl.. Normally a USGI chambered barrel will "swallow" the go and no-go SAAMI gages. Search the threads here on TFL to understand the difference in chamber lengths. dozier
Not my rifle...looking about buying it. All USGI like new condition built several years ago. Barrel an bolt are Winchester....do not know what gauges were used, his gunsmith had built several though...
 

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Not my rifle...looking about buying it. All USGI like new condition built several years ago. Barrel an bolt are Winchester....do not know what gauges were used, his gunsmith had built several though...
If the GS is using SAAMI spec gages, and your bbl is a USGI Winchester. It falls within the tight end of a 7.62x51 chambering. I would say that commercial ammo can be used in the weapon. If he is using NATO spec gages, the chambering might be a little long for commercial ammo, and you might have to stick with Military ammo. It would pay to find out which gages were used. dozier
 

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Discussion Starter #9
OK, I'm drawing a bead on this...I believe that if chambered for
.308, I can also shoot Military ammo through it as well....if its chambered for USGI specs for Military ammo, then it isn't good to shoot commercial .308......right?
 

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