I am not sure what mapsjanhere means by threading the magazine tube, though.
The alternative is taking the barrel off the receiver (without damaging either) to put the barrel in the lathe for a good crown, reinstalling the barrel to the correct headspace and torque, and, after everything else is done, putting the gun on the mill to get a nice square dovetail cut for the front sight. All that takes time, and I haven't seen many gunsmith lately charging less than $70 per hour.