10/22 Headspace
Larry Burchfiel,
Headspace on the "Ruger" 10/22, and most 'blow back' .22LR rimfire guns, is controlled by the depth of the recess in the bolt face, as the bolt closes completely onto the breech face of the barrel. Therefore, one would use a depth micrometer, or for a less precise measurement, a caliper, and measure the depth of the recess in the bolt face.
.22 Long Rifle: .0425" GO [minimum], .045" NO-GO [maximum] [CPC]
Changing the headspace is best left to the professionals like Randy at CPC; however, it is normally done on a surface grinder, as the bolt is surface hardened. Firing pin protrusion must be checked and corrected as necessary after the work is complete.
Hope this helps.....! !
