This will be quick- not because it isn’t an important topic, but because the reason is simple and, for anyone who thinks about it for a minute, pretty obvious.
Whether a vintage or modern mass market mouthpiece, it has been finished by hand to some degree. And, almost always, the work was done by someone who had a quota to finish by lunchtime. Yes, I like to think that in an earlier era, there was a more apparent pride in workmanship.And, there likely was.
But a quota is a quota ,and the people who did the work were and are anonymous, and one mouthpiece in a box is as good as another. Even way back when. When you’ve actually played enough of these vintage pieces, you find out.
That said, there are still some fabulous designs from days gone by, but almost all of them are incomplete and unfinished, as far as a player is concerned.
The same is true, maybe more true, of many modern pieces. And it’s for the same reasons.
So, you really don’t know whether a (fill in a name) mouthpiece marked 6* is anywhere near complete or even a 6* at all.
So, if you like but don’t love what you’re playing now, consider having that piece looked over for rebalancing.
Read what players have said about their rebalanced pieces. It’s true.