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Head Space Gauge

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14 July 2004, 14:25
trigger
Head Space Gauge
Just got my Forester Go and NO Go headspace gauges from Midway 243,260,7-08, 308.
Go marked 1.630
No Go maked 1.634

Tried NO Go in four different guns and the bolt closes on all 4.
Browning A-Bolt 7mm-08 2002 vintage
Parker Hale 98 Mauser knock off in 243 Win
Two Rem 788s in 308Win. from 1973

The only one that I have loaded for exclusively is the A-Bolt. And nothing hot at all. 42 grains of Varget with a 140 Nosler BT.
The 788s mostly shot factory. I have loaded some and my dad loaded some for them. Never any blown primers or hard extraction.
The Parker Hale I don't know it's history, but does not show signs of excess head space. Never had a head seperation.

Could this be a bad/mismarked gauge or do I have 4 guns with excess headspace?
Send it back to Midway?

Thanks
14 July 2004, 14:53
thefinegunmaker
Make sure you have a stripped bolt without ejector. If the bolt FALLS on the NO-GO then you have excessive head space. If you can force it then it is probably still in spec. Don't force it, you may break the gauge.
gunmaker
14 July 2004, 15:09
trigger
The finegunmaker

Curious only. But what difference does the ejector make in using the NO Go gauge?

Thanks again
14 July 2004, 15:33
thefinegunmaker
The spring loaded ejector like in your 788 will not allow you to drop the bolt on the go gage. You will have to force it past the ejector spring. The closing cams on the bolt/receiver can allow you to force the longer gage into a shorter chamber.
gunmaker
14 July 2004, 19:35
wallyw
Quote:

The finegunmaker

Curious only. But what difference does the ejector make in using the NO Go gauge?

Thanks again



Unless I've got the bolt apart for some reason (such as a rebarrel/rechamber) never could see what effect a plunger ejector could possibly make.
15 July 2004, 00:55
irv
Many rifles will force a no-go gage into the chamber (the 1917 being one of the worse due to angled lugs).
Close the bolt and feel for the chamber touching the shoulder of the gage.
I really doubt if all of your rifles have headspace.
Good luck!
15 July 2004, 03:01
Headache
Trigger,

There is nothing wrong with your rifles. The SAAMI industry standard for the 308 family of calibers (this is also the military standard) is 1.6300"+.0002" for the GO and a maximum of 1.6400"-.0002". The FIELD guage is 1.6380"+.0002". If a rifle take the FIELD gage, it is time to take a look at it, but it is not unsafe unless it takes the Maximum gauge. The industry sets their own standard some where in between SAAMI minimum and maximum. Usually around 1.637" for the 308 family.

The Forester guages I believe are manufactured to a tolerence of +/- .0005 which could conceivably give you a guage of 1.6335" to 1.6345". Most other manufacturers grind theirs to +.0002 on the GO to -.0002 on the NO-GO or max.

Hope this helps,
Headache