Thanks for the time you spent on this topic. I have read some of the same things but still find something new in others perspectives. I am a patrol officer and am very familiar with my m-4. I have put over 35,000 rounds through it in the last five years. It cost me a new barrel, 5.56 16" bull, and other odd and ends. I have shot both 5.56 and .223 ammo, 55 gr. to 68 gr., out of my m4. I carry Speers GOLD DOT 5.56, 55 gr. PSP, on duty and 5.56 NATO green tip for everything else from hunting whitetail deer to target practice. I preach to my guys to practice as if it was real world issues. The only thing that I stand by is sighting in at 50 yards. This gives you a dead on again at 200 yards with only about 6 inches of play. I do this due to all possible shooting incidences that officers are involved in are close quarters. Anything past about 100 yards I better have a scoped rifle covering me. Thanks again.