Gunsmithing Question-Threading a Proof Carbon Fiber Barrel for Muzzle Device

[stompbox]

Question for you gunsmiths who have threaded the muzzles on proof carbon fiber barrels. I'm doing my first carbon fiber barrel and I want to thread it 5/8-24 for a suppressor. I usually like to indicate the muzzle end in a 4-jaw and have the breech end in the outboard spider. The Proof barrel only has about .800 of exposed steel on the muzzle end. That would only leave about .150 of steel to clamp on in the 4-jaw, so I would end up clamping down on the carbon fiber also. I do have copper pads on my jaws so I don't mark up the barrels. Will that OK or do you have to use a live center in the muzzle and have the breech end in the chuck? I hope I worded this correctly and my question makes sense. Thanks

 

[Supersubes]

You can clamp the carbon. Proof recommends you spread the load out when doing so. I use the same method whether carbon or steel barrels and use a still ring. Do you normally just clamp tapered muzzles in your flat jaws, or take measures to fill the gap that’s present out near end of each jaw?