Originally Posted by
Winger Ed.
I'd think it would relate more to how many times and how violently a cleaning rod went up & down it.
I wouldn't bother with doing a bunch of research,
but I sure do pay attention to the crown and look for visible damage to the crown when buying a used rifle or handgun.
I've only seen a couple over the years, but I have noticed excessive wear on one side of a muzzle or two
where the bluing & 'shine' on the lands & grooves was different from one side to the others.
I have no idea how they'd shoot since I didn't buy them.