Like Steve, thread 20, so am I. A great project to resurrect something previously worthless(?). But you could simplify the CHS aspect up a bit Mr E by calculating that the face of the bolt is the 'stop and work forward from there, to the original face of the barrel, between which the original CHS was measured.

A .22" CHS gauge set is east to make. Can anyone remember the CHS criteria for the No2 rifle. It didn't change over the century as the same gauges remained the same for the No8 rifles! and are still in use today! If you need the spec MrE, I'll see if I can't measure mine or just look it up - if I still have the EMER!!!!!