I have spin-indexer, and know that it rotates 360 degrees in one degree increments.
Here's the indexer I have, it cost me 29 bucks on sale. ( Click image to enlarge. )

Here's the front of the indexer, with a 5c collet ready to use. - You crank the handle on the back to tighten up the collet, once you have poked something in there.

To get the bolt in the indexer, I used a screw-in heat sink that I bought long ago on eBay, for welding on bolt handles to Mauser bolts.

It screws into the back of the bolt ( after firing pin removal ) like this:

The turned-down section on the end is .625" in diameter, so I chucked up a 5/8" collet in the indexer.
Here it is, ready to be moved over to the milling machine, or a drill-press with a cross-slide.

I am thinking about making a home-made tailstock that will engage the firing pin hole with a bit of polished piano wire, or something like that - but it may not be necessary as the indexer is pretty rigid, once it is bolted down to the mill, and the pressure used in jeweling is very light.
At any rate, this is how I ended up not having to buy or make a bolt jeweling fixture. When I get the new bolt handle finished up and the bolt polished, I'll be in good shape for jeweling it.
I thought maybe some of the other guys here might have a spin-indexer laying around, and need to jewel a bolt.