stagpanther
New member
My first go at doing this, I bought this 350 legend AR barrel a couple years ago for an AR build, I never liked it because it didn't group well--especially compared to my savage bolt gun. I decided to pull it out of the back corner of the safe and take a second look, after I pulled the brake off and put my Hawkeye through the muzzle I discovered a large gouge on the crown which traversed the bore and rifling. The interesting part is that it seems like the exiting gas was eccentrically turbulated so that an area of "backwash" erosion had started forming around it.
I decided to give Brownell's crown cutting tool a go and went with a simple 90 degree cutter, in retrospect I wish I had bought the 11 and 45 degree ones at the same time, I really had no idea what I would need. The cutting at first seemingly went nowhere, that's when I put a flat file to it and got through the first thousandth or so, after that the cutter had no problem at all, I'm guessing that there was some kind of treatment that made the layer of steel immediately under the surface extremely hard. Everything now is clear of defects at the muzzle mouth and very sharp, clean edge. I went ahead and put the muzzle break back on--but was wondering if it still would be better to chamfer the inside and outside of the crown--or do I have nothing to worry about (as long as I have something over it)?
I decided to give Brownell's crown cutting tool a go and went with a simple 90 degree cutter, in retrospect I wish I had bought the 11 and 45 degree ones at the same time, I really had no idea what I would need. The cutting at first seemingly went nowhere, that's when I put a flat file to it and got through the first thousandth or so, after that the cutter had no problem at all, I'm guessing that there was some kind of treatment that made the layer of steel immediately under the surface extremely hard. Everything now is clear of defects at the muzzle mouth and very sharp, clean edge. I went ahead and put the muzzle break back on--but was wondering if it still would be better to chamfer the inside and outside of the crown--or do I have nothing to worry about (as long as I have something over it)?