Let me pose a question since I have a bunch of X bullets I would like to shoot. Since barrel manufacturers typically advertise bore and groove diameters to .xxxx" and have the equipment to measure to that precision, would it not be fairly easy to experiment with an old set of barrels and put the question to rest to a degree that would satisfy most readers if you could get someone to undertake the task. Since this the 21st century, may be able to crowdfund the project amongst the shooting community to get an answer.