Serious question for you AR experts. How much would this amount of damage actually effect the functionality/safety of the rifle?
Personally, I don't think I'd ever even consider grinding the locking lugs on any of my rifles, but it's interesting to see that not everyone is as reticent as myself. Maybe he was going to do some kind of 'Mythbusters'-like test, where he ground more and more of the lugs offf until he ended up with a load of scrap metal embedded in his head?