Randy,
I didn't think anyone would catch on to it...but your smarter than most. The question came up if I was boring or reaming. I looked up boring in the American Heritage Dictionary and they said...monotonous, tedius, irksome, dismal and dreary. I knew that wasn' t it so I checked reaming and it said thus.......to form, shape,or enlarge a hole. Good enough for me... its reaming instead of boring. Its me who is boring. Anyway, your question might be that if the raceway and the threaded portion of the receiver and not in line then what good does it do to ream it. Well, most factory receivers are not but they are untill they go to heat treat and then the nose is turned red hot and dipped and there in lies the problem. As you know most custom actions are heat treated first and so this is not a problem. So, by reaming and using the reaming mandrel as a indicator the action with the reaming mandrel in it is set into a special holder where it can be adjusted to no runout. I go back in and turn the threaded portion untill it is concentric and parallel to the raceway or mandrel. I have not found one that was over .015 out of round (most are egg shaped) and after removeing that amount or less I single point cut the threads and go .015 or the amout I took out deeper. Thus we have threads and raceway parallel and concentric. At the same time I touch up the integral lugs and the face of the receiver. One reason why some actions don't shoot well is that the bolt and raceway are not parallel with the bore of the rifle. The face of the bolt and the back side of the lugs should be trued also. This is a good time to install a new bolt that is CNC ground like the Pacific Precision or sleeve with a one piece sleeve over the existing bolt. When installing a new barrel on a factory 700 action it is important that you true it up. Mainly to make sure that the threaded potion is in line with the raceway but the barrel and receiver should match perfectly. In other words when you tightend the barrel you want it to hit the same all the way around the shoulder on the barrel if it does not then you start to stress the receiver and your re-barrel job is not the very best it can be. You eliminate many problems by doing this but thats another story and I am getting long winded here.