Jose;
The two major types of choke constriction encountered are the conical/parallel & Taper. On the first type you have a cone section which reduces the dia of the bore which is followed by a short parallel section at the muzzle. On the later the entire choke section is a cone ending at the muzzle.
Imagine two bbls both having .729" (18.5mm) bores & choked to .690" (17.5mm), one having each type of choke. Then imagine inserting a solid rod which will just enter the choke to a depth equal to the length of the choke from the muzzle end. If you then tried to "Rock" that rod the one in the parallel choke would be un-movable, but the one in the taper choke could rock until it hit the angle of the choke wall, as it only has that one point of contact.
I can assure you that an adjustable reamer can do the same & will cut at what ever angle it happens to be started in this case. After the first few cuts create a parallel it will then tend to follow that parallel whether it happens to be in line with the bore or not. Those first few cuts however are totally dependent upon "EyeBall" alignment to the outside of the bbl, one can't see the bore while doing the reaming.
Of the guns you mention I know that some of them had & highly suspect they all had the conical parallel chokes, which would account for your positive results.
I do appreciate your input on this & hope my explanation clears up what I was saying. Successful operation of one of these adjustsble reamers for this task is dependant on taking only very light cuts & being very careful "Not" to apply any sideways pressure. If enough sideways pressure exists to hold the cutting edge into the meatal they can cut on one side only.
