ive threaded well over 100 barrels for myself and other people.. ive found the best way to get it right is to build a jig(aka setup tool) that inserts in the barrel so that u can locate off the i.d. of the barrel i have never picked up a barrel that the i.d. and o.d. were true to each other... But i can say that the smiths r pretty close... i did go ahead and put an 11* target crown back on mine causr the 1/2-28 threads leave a sharp edge with the recess that is cut from the factory... and i may need some help on those pics havent figured it out yet lol