Like I said, when the bur is/was removed it functioned fine yes?
Anything can be damaged or broken, that's not the question. The question is whether or not dry firing on any level let alone a lot will cause enough damage to be of concern. Based on the photos above, it appears some need to do a better inspection when cleaning. Such a bur shouldn't get so pronounced before being addressed.
Gunsmith suppliers(which are just another business) also those fancy gunsmithing blocks for pin removal and bore guides. Neither of which are necessary. They will sell whatever people are willing to buy, they have little interest in selling only what's necessary for any given task.
Its called a jewelers file and they fit nicely. If you're brave and steady enough a dremel or similar rotary tool with a stone bit works just fine.
TDC
I don't believe that sticking a Dremel or a file in the chamber of any gun is a good idea....... The only thing going in any of mine is a properly sized reamer. Bravery is not a good reason to screw up a chamber.




















































