6" .30 Luger barrel, 1900 style

[ithacaartist]

When I talk to the guy about clocking, indexing, and proper barrel vise and system to hold the extension without damaging it, and finally headspacing check/adjustment, I should be able to gauge his abilities. I'm hoping, as is very possible, that the replacement will crank right on just fine, however, I'm also aware that clocking and headspacing have their own needs and remedies. If he says he has a .30 luger chamber reamer already, I'll begin to think we can do it here. He's also a machinist, and even though he might not have specific Luger experience, I think we'll be fine.

One more question: I've seen the dimensional range for proper headspacing discussed before, not too long ago. Could someone with the figures please post them? My search didn't turn up the post I wanted...