I'd like to get a feel for just how out-of-whack an action really is before it is "corrected". This primarily concerns Rem 700s but may of course apply to other brands. 1.) The barrel face. Is this surface not flat enough and/or not typically cut at 90 degr to the bore centerline from the factory ? 2.) Barrel threads. If the threads are not rusted/damaged, why would they need recutting ? Are they also not typically 90 degr to the bore coming from the factory ? 3.) Bolt lugs. Do the locking ramps wear down enough to need resurfacing ? I do appreciate the potential benefits of "blueprinting" an engine but I wonder if all the benefits translate to a rifle action. In a 700 it seems to me that even a brand new action/bolt assembly is a bit loosy goosy, but I don't have years of experience here and my suspicions may be unfounded. Now, when rebarreling, I understand that in order to set headspace, several dimensions must be juggled and set to work together. So is the rebarreling scenario primarily when an action would need any "corrective" machining ?