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30/06 go no go gage for Garand
- Thread starter Zdragunov
- Start date
Do you want military head spacing gauges or SAAMI? Military is set to a different spec as SAAMI is less generous or tight.
You will find the numbers between SAAMI and Mil psec to be confusing, SAAMI moved the Datum line on the SAAMI spec gauges.
That's why the Mil spec and SAAMI look different.
SAAMI is GO 2.0487, No Go 2.0587.
The U.S. Ordnance specs are: Go 1.940", No Go 1.946", Field is 1.950 (The "Field" gage is a military gage that is longer than No Go.
It represents the longest head space dimension the rifle should have to remain in service.)
Quick note, if you use SAAMI gauges in a garand, you will most likely find that you have a bolt closing on a No Go. Commercial .30'06
and mil .30'06 are measured differently, SAAMI is tigher.
Pete
You will find the numbers between SAAMI and Mil psec to be confusing, SAAMI moved the Datum line on the SAAMI spec gauges.
That's why the Mil spec and SAAMI look different.
SAAMI is GO 2.0487, No Go 2.0587.
The U.S. Ordnance specs are: Go 1.940", No Go 1.946", Field is 1.950 (The "Field" gage is a military gage that is longer than No Go.
It represents the longest head space dimension the rifle should have to remain in service.)
Quick note, if you use SAAMI gauges in a garand, you will most likely find that you have a bolt closing on a No Go. Commercial .30'06
and mil .30'06 are measured differently, SAAMI is tigher.
Pete
There is really no practical difference between the military and civilian .30-06 gauges. It's tough to find military gauges nowadays, so you are stuck with the civvie/SAAMI gauges. I have both the Clymer and Forster gauges as well as a military 'go' gauge. The Clymer 'no-go' gauge is actually a bit more generous/longer than the Forster and seems to approximate the Forster 'field' gauge. You can also reverse this and contend that the Forster 'field' gauge may be a bit short. Bottom line; you can install a bolt or check headspace using either the Forster or Clymer gauges and you are good to go.
When checking headspace on a Garand it is equally important to verify that the bolt closes w/o resistance on the 'go' gauge. The reason for this is that the spring driven Garand bolt lacks the camming power of a bolt action rifle on closing, thus increasing the possibility of an out of battery detonation where the bolt may not be fully closed on a chambered round. The receiver bridge interaction with the 'tail' of the firing pin provides a secondary safety feature here, but best not to leave this to chance. Both the military and the Clymer gauges have a rebated end to permit use with the Garand ejector still in place, but it is best to strip the bolt when checking headspace.
When checking headspace on a Garand it is equally important to verify that the bolt closes w/o resistance on the 'go' gauge. The reason for this is that the spring driven Garand bolt lacks the camming power of a bolt action rifle on closing, thus increasing the possibility of an out of battery detonation where the bolt may not be fully closed on a chambered round. The receiver bridge interaction with the 'tail' of the firing pin provides a secondary safety feature here, but best not to leave this to chance. Both the military and the Clymer gauges have a rebated end to permit use with the Garand ejector still in place, but it is best to strip the bolt when checking headspace.
