I bought this die for AR15 barrel threads. The barrel had a muzzle brake which, when removed, had deposits in the threads flattening about six (6) threads about halfway up. After screwing the die on with the die holder and some Kroil oil, I screwed the die onto all the threads, unscrewed and did it a second time. The die worked well and cut threads sharply and accurately. It definitely cleared up what would have been a useless trunk. The new muzzle brake went in with absolutely no problems. Great tool.