Interesting this is about a TC. When I bought my TC Encore .223 barrel, years ago, the crown was really rough.
I recrowned it using a large ball bearing and some sandpaper. I placed the sandpaper on the muzzle, then pressed the ball bearing down over the bore, pressing the sandpaper into place and pulled the sandpaper up around the ball so I could get a grip on it. Then I pressed and twisted the ball bearing/sandpaper a few times, turned the bore a quarter turn, pressed/twisted it again, turned the bore a quarter turn, and kept that up until the sandpaper quit cutting from wear. Then I moved the paper slightly to use a new section and started again.
When I could see that the paper had cut all around the crown, I went to a finer grade of sandpaper and went through the process again and kept it up until I was happy with the result. The barrel is stainless and after shooting, the muzzle blast made a perfect star pattern on the muzzle and the three shot test group was under half an inch.