Checking your M1 Garands Headspace

First step is to get yourself a set of headspace (Go, no-go, and field) guages or at the least a field gauge. The Go and no-go are not really needed unless you plan to rebarrel and finish ream.
Strip your bolt, removing the firing pin all the springs and the extractor.
The gauges go into the chamber and contact the bolt head.
Never force the bolt light finger presure only.


The bolt should close completely on the Go gauge


The bolt should not close but often does close on the  No-go gauge. If yours does do not worry too much. This means there is more headspace than the GO, but it is still safe for military arms..  If the bolt does close on this guage make sure you test with the field guage. It should look similar to photo below below.


The field gauge is the most important for the collector. If the bolt closes on this guage you should not fire the rifle. You could attempt to try other bolts to see if this corrects the problem, but more than likely you will need a new barrel. The rifle should never close on this gauge and should look similar to the photo below.


900K garand headspacing check by A. Corapinski