First of all, I think that we need to limit the discussion to top grade barrels particularly since I am not aware of any new factory rifles that are available with cut barrels. Looking at the process normally used for top grade barrels, both button and cut are drilled, reamed and either lapped or honed with one of the new Sunnen machines before rifling. If all is well, at the end of the lapping or honing there should be no tool marks. As far as why Shilen makes two grades of barrels, I believe that they do not want to throw away that part of the barrel business that does not want to pay for the extra labor involved in lapping after rifling. Getting back to the question a friend used to build some of the very best M1A service rifles and he told me that in that application cut last longer than button, but for customers on a tighter budget he still built rifles buttoned barrels. Either one can produce gratifying accuracy. I have seen it. On the stress relieving of cut barrels Kreiger's cryo treatment of blanks before they are drilled improves drilling results. Years ago he told me that for that reason alone it was worth the cost. A relatively new barrel maker Proof Research sells some of their barrels without carbon fiber wrapping. As I understand they heat stress relieve their blanks and they are a cut barrels. A friend who had done a number of builds with their wrapped barrels tells me that unlike some other wrapped barrels, theirs feel uniform from end to end when he pushes a cast measuring lap through them, and they look good when examined with a bore scope. As far as I am aware no one is using the unwrapped barrels in competition but the wrapped ones have given my friend excellent results for hunting builds. One variant on the button side is Broughton's stress relieving after contouring in addition to the usual heat stress relieving that is standard for all button barrel manufacturers. My friend cast laps as a routine matter, to measure bore dimensions and look for tight and loose spots. He offers this service to customers to save time and expense by not working on a barrel that has problems that cannot be fixed. He also does this to new, unchambered barrels to protect himself from wasting time on a barrel that has issues that require replacement.