Diamond makes them. They need polishing and hardening. So, they become a 200$+ repair on a sticky $400.00 gun.
I have a couple here.
I was just informing the OP about real life shooting a Flues in vintage shoots.
They aren’t a 200 rounds a week gun.
So you practice with a Dickinson, and shoot the Flues at the event.

Or, just send another to the recycler.

Out there doing it best I can.