With a case at the 2.410 length, it showed the chamber that had been cut for the 405 x 2 1/4 needed attention and because I had to time the barrel to my action this was not a concern. The barrel (being a take-off) had been sleeved to within a 1/16 of a turn to a friends action before the barrel was sent to me so in short order it was timed to mine and removed for the chamber work

Slow and with plenty of cutting fluid (ok, I used ATF)and with many checks for depth and to clear the sludge from the cutting flutes

Finished

Filing in the extractor groove

Breaking the mouth of the chamber