Are there any special considerations that need to be addressed when indicating and/or chambering a Proof barrel?

I typically chamber with the barrel thru the headstock, using a 4-jaw on the inboard side and a spider on the outboard side. When chucking the barrel I tighten the jaws against a piece of 4ga copper wire that is wrapped around the barrel. On the outboard side I try to use brass shim stock under the bolts in the spider. All this of course is with CM or SS barrels. Should I be doing something differently with the CF wrapped barrel?

Never done one of those but I would be a little hesitant to clamp on the CF. Maybe its not an issue but before I ruined something, I would be calling the company to find out what they say. I would think that shim stock would help spread the force so you don't compress the CF, if that is even possible.

The one I did I was able to keep the chuck jaws on the SS portion of the shank. I use a spud into the muzzle end that is also my flow through coolant nozzle so didn't have to worry about clamping on the muzzle. If I was to use a spider and it had to tighten on the CF I'd probably put a wrap or two of some kind of tape between the CF and the shim stock and even then be pretty gentle on the screws.

Thought about going a step further and turning a collar with the correct internal taper, splitting it, and then sliding it over the CF portion of the barrel and letting the bolts from the spider press against the collar.

you might be better off using a collet chuck

And turn the barrel between centers? Use a steady rest? Parrish the thought. That's why they make lathes with short headstocks. LOL

FWIW, I haven't yet acquired a collet chuck, nor have I made a collet closer for my lathe.

I would make a split collet to put on it.

If you can swing proof tubes, you can afford a TBAS.

I put them through my head stock just like any other barrel. On the chamber end there is plenty of steel to grab and on the muzzle end you don't need to grab them very tight to maintain alignment. I do about 3 or 4 a year.