The Forster Headspace Gauge is designed to ensure accurate testing of chamber headspace. Headspace is the distance between the face of the breech and the base of the cartridge when the action is closed. Safety and accuracy are threatened when excessive headspace exists.
For best results with bolt action rifles, remove the extractor from the bolt. The bolt must work freely in the receiver. It is impossible to have the proper feel for a gauge if the bolt is too tight or sticky.
Insert the proper gauge into the action. Attempt to close the bolt on the gauge. CAUTION – NEVER FORCE THE BOLT CLOSED on a gauge. A rifle with correct headspace should close easily and without feel on the GO Gauge, but should not close on the FIELD gauge. If it does close on the NO-GO gauge, but not on the FIELD gauge, the rifle may still be serviceable. However, it is not advisable to use it for best accuracy with factory ammunition.
CAUTION – ANY RIFLE THAT WILL CLOSE ON THE FIELD GAUGE MAY HAVE DANGEROUSLY EXCESSIVE HEADSPACE AND SHOULD NOT BE FIRED UNDER ANY CIRCUMSTANCES.
There are 3 lengths of headspace gauges available per caliber:, GO, NO-GO & FIELD.
This item is for sets of gauges. In most cases a set consists of 3 gauges as per above, however in five calibers (250 Savage, 378 Wby, 416 Wby, 460 Wby & 7.62×54 Russian) there are only 2 gauges manufactured, NO-GO & FIELD. One set (6.5 SKAN) has two gauges, GO & NO-GO.
The products in the drop down menu below are complete sets of gauges.
GO length – This checks the rifle to see that the chamber will accept the cartridges made to SAAMI specifications.
NO-GO length – This is used by most gunsmiths as a maximum headspace gauge when chambering a rifle’s headspace dimension. If a rifle closes on a NO-GO gauge, it may have excessive headspace. If a rifle closes on a NO-GO gauge, it may still be within the SAAMI Rifle Chamber tolerance. Next it should be checked with a FIELD gauge.
FIELD length – If a rifle closes on a FIELD length gauge, its chamber is dangerously close to. or longer than, SAAMI’s specified maximum chamber size. This is the longest of the three gauge lengths.
Please select the caliber of the set you require from the drop down menu below and then select ‘Add to Cart’.