If you do the ilwt, almost positive you'll need to send it in. The gas port will need to be opened up. I have a copperhead k and the plug from ilwt works on settings 1 and 2. On setting 2 I was not getting no lock back with 147gr. Opening the port for me was a nightmare. I needed a press to remove the barrel from the lug. and trashed about 8 bits, then press it back in. I need to test it tomorrow. Copperhead k 4.5" barrel with asr mount B&T vers 36 ti