When chambering or crowning a barrel in the lathe how much run-out is acceptable --is .001 too much--what are your thoughts. I understand different gunsmiths may have different opinions. thanks in advance for your opinion.  leadball

Paul- ALWAYS strive to get as close to zero runout as possible, even when using a "floating" reamer holder.  "Dead nuts" is cool!

Leadball, you've received some excellent advice, these guys are right on.

There are two basic ways to approach the lathe setup, i.e. through the headstock vs in the steady-rest. Your approach to TIR depends in large part upon the method chosen.

The through-the-headstock method is the one preferred by most high-precision workers. It requires much greater attention to detail in having everything exactly perfect, but will sometimes give more accuracy on the target IF everything is indeed perfect in the setup. Requires a large headstock spindle hole and a spider on the rear of the spindle but does not require a long lathe bed. This method magnifies any setup errors but minimizes any machine errors.

The steadyrest method is the one favored by most gunsmiths & is the method typically taught in the various smithing schools. It doesn't require quite as much precision in the setup and is much much faster as a result, but is considered to be less precise and possibly less accurate. All errors of setup are minimized with this method but the errors built/worn into the machine cannot be minimized as in the headstock method. Requires a long lathe bed but can be used with a small spindle hole & no spider.

The book Precision Rifle Barrel Fitting by John Hinnant is far & away the best text I've ever seen on the subject, well worth the money regardless of your level of experience. From Brownell's.

FYI FWIW most Benchrest shooters pay big bucks to have their bbls machined with the through-the-headstock method. This is where you need to be dead nuts in your setup, this method WILL double any setup error but CAN also zero out all setup errors and all machine errors if the operator is good enough. Be prepared to spend at least a full day's time on the headstock method while the steady-rest method can be finished in 4-6 hrs for fitting, chambering & crowning.

Like the madam said to the bishop, you pays your money & you takes your choice. Good luck, Joe

PS At one time I had plans with another poster/member for a pair of  Journal articles detailing the two methods, both perpetrated on the same brand of bbls and the same sort of single shot rifles. Maybe we need to dust off those old article plans & get 'em to the new Editor?

The reason for the question on run-out --getting to .0005 is within my limited capabilities--but from there on down to nothing seems impossible. "so far"        leadball