The Forster Headspace Gauge is essential for checking the chamber length of a rifle for safety and accuracy, especially when chambering a new barrel or buying a used gun.
It is manufactured to SAAMI specs, with the .30 M1 Carbine Field Gauge being .0005 inch under 7.62 NATO NO-GO dimensions.
The gauges are machined steel and interchangeable between calibers that share the same stock number, covering a wide range of cartridges.