Necessary when finish chambering a barrel or when checking the chamber of a used gun to be sure the headspace dimensions are within safe limits. This is a Go Gage only. Both a Go Gage and a No Go Gage are required to properly headspace a barrel.
These Go Gages represent the lower limit of SAAMI specifications for proper headspace dimensions. If the action closes with this gage is inserted, then the firearm is within acceptable minimum headspace dimensions.
Technical Information
SPECIAL NOTE: If you are having problems with your Forster headspace gage, Forster has requested that you contact them before returning any headspace gages to MidwayUSA. They can be contacted by phone at (815) 493-6360 or by email at
info@forsterproducts.com
Material:
A2 Tool Steel
Notes:
Go Gage:
Ascertains correct headspace dimensions by duplicating the minimum allowable distance, from the case head (or boltface)
to the datum line of the cartridge's shoulder, allowed within the chamber to secure a loaded cartridge and allow the breech to
be closed in a safe manner for firing.
If the firearm locks up in battery when the gage is inserted, then it is within acceptable minimum headspace dimensions and may be used.
No-Go Gage:
Duplicates the distance over the maximum allowable, from the case head (or boltface) to the datum line of the cartridge's shoulder,
allowed within the chamber to secure a loaded cartridge and allow the breech to be closed in a safe manner for firing.
If the firearm locks up in battery when the gage is inserted, then it is not within acceptable maximum headspace
dimensions. The firearm should not be used and should be examined further by a knowledgeable gunsmith.
Field Gage
Duplicates the maximum allowable distance, from the case head (or boltface) to the datum line of the cartridge's shoulder,
allowed within the chamber to secure a loaded cartridge and allow the breech to be closed in a safe manner for firing.
If the firearm locks up in battery when the gage is inserted, then it is at the maximum acceptable headspace and should be examined further by a knowledgeable gunsmith.