[archy]

Primary headspacing is usually set as you describe - where the barrel and receiver join (at least for most 20th-century military rifles). There are oddballs, though - in tilting-bolt designs like the SKS and the FN-FAL, headspace is tweaked by adjusting the thickness of the bolt locking shoulder. The HK G3 (HK-91) and its small-bore relatives rely more on bolt-to-bolt carrier gap than headspace, due to the roller-locking design being adjustable with different diameter rollers.

And as on the British Number 4 series Lee-Enfield rifles, that use interchangable front bolt faces in different graduated lengths to make the adjustment, used with the rimmed .303 British MkVII cartridge. Works like a charm, all you need is a headspace gauge and a selection of bolt heads.

[Charles Martel]

I recall first reading your comments on the No. 4 Lee-Enfield over on the Tom Bowers “Sword of Damocles” message board. Interest in the No. 4 as a SHTF rifle had bubbled up there for a while. Might’ve been during the run-up to Y2K.