How to headspace?

[Peter Laidler]

You don't need feeler gauges TR, you just need the two GO and NO-GO gauges. I always used to CHS with the actual gun breech block LESS the extractor assembly. Gage into chamber gun nose down on the bench without the butt slide fitted, breech block fitted into piston extension*. Slide extension slowly forwards under finger control. It must fully lock-up and 'fire' on the go gauge. Same again and it should NOT fully close and as such will definately NOT fire on the no-go gauge. As simple as that

* we had a load of slave items used for these sorts of tests in the big workshops and had a slave piston extension without the piston for these sorts of tests. But it MUST have the piston post as the striker must indent the wax filling in the end of the CHS gauges. This shows actual FPP in real time.