My experience with Briley tubes has been that your nominal bore is taken into account when they size the chokes. If you want a 0.20" constriction, it is immaterial to them whether you have a 0.728" or 0.738" bore - the final product will have a 0.20" constriction. I guess that is fitted, hmm?
How seamless the transition from bore to choke tube is another matter. Regardless of the source, my observation has been that all tubes have a tapered skirt that tucks back away from the bore so that none of the charge will catch on the thin end of the tube. Depending on the tube, that skirt may open the bore 0.010" or more before the tube contricts again to choke dimensions. Is that what you meant by fitted?
