No need to use the steady. The barrel OD is unlikely true to the bore ID so you probably don't want to use the steady anyway. Just use a Newlon Precision
http://www.newlonprecision.com/ crown saver and an NC live center in the muzzle with the breach end of the barrel in the chuck. You don't always have to use an NC center but it gives you more working room especially on a small dia barrel. The crown saver won't hurt the crown and centers the barrel to the bore. If you don't want to remove the barrel from the action you can make a tight fitting mandrel to fit the bolt raceway and use setscrews through the action bolt holes to lock it to the mandrel. Put the mandrel that is mounted in the action in a four jaw, the muzzle w/crown saver in the NC Center and dial in the mandrel at the chuck end. If you are careful you don't even need to remove the trigger. If you use a mandrel make sure you turn a shoulder on your mandrel so it cannot be pushed back into the chuck while under pressure of the center at the muzzle and put some flats on the mandrel for the setscrews so the assembly doesn't spin on the mandrel. Also when you make the mandrel put a 45º or 60º on the front end and make it long enough so the beveled end will butt up against the back of the chamber. When you need to check for thread fit carefully pull the tailstock back while supporting the barrel and the crown saver should stay stuck to the muzzle. Brownells carries the crown savers too but I think they are cheaper direct from Newlon.
