The only thing that makes a bushing "match grade" is the fit to slide & barrel. Drop in fit implies that it has clearance that a match bushing would not have. If your goal is to get a snug fit without fitting, then use your calipers to measure the inside diameter of the front of the slide at several spots & the outside diameter of the barrel several spots. all slides/barrels will vary a little. Look in Brownells & order the one that give you the closest fit. Better yet, call them up, give tech support your measurements, & ask them to pick you out one. Realize that the barrel has to tilt in the bushing at lockup, so pick an inside diameter that gives at least half a thou clearance. You can also expand the bushing skirt to fit tighter to the slide without affecting the bushing/barrel fit. Since the bushing does not move with reference to the slide during firing, the fit here can be as tight as you want it without affecting reliability. Just how much effort to disassemble.