I'll have to update this thread when I finish with my latest, a 1" 12 twist 25" blank that I picked up. I contoured the barrel for a medium weight AR blank, .875" gas block 22" finish (cut to length AFTER lapping) then lapped the bore. It REALLY didn't take much more than a few minutes. Borescope before showed very fine reamer marks the entire length but I couldn't feel them while pulling the lap. After maybe 20 strokes or so and a few more towards the breech end I borescoped it again and all but a few very faint reamer marks were left in the center of the lands if I remember right. Couldn't feel any tight or loose spots and it seemed to have a slight choke towards the muzzle, which is what I wanted. I'll try and finish it up in the next week and shoot a few test targets with it. I expect 1/2" or better and the bore looks as good as any Shilen I've borescoped. I can't tell you how the dimensions are, they very well may be a touch loose, and that might contribute to a little less velocity but accuracy should still be very good.