Yeah, we talked it over this afternoon when he brought the upper back to me. Said when I told him what it was doing, "barrel nut" was what came to mind, and he said he has seen a few over the years, usually from home-builds. Agreed that you almost never see that with a factory rifle. With it being an 11.5" barrel, it was hard to spot just looking down the barrel shroud, but when you took the "suicide look" from the muzzle end, you could see it. He said once he took the shroud off, the barrel and gas tube looked good. Started playing with the hand guard, and spotted it then. He took a pic and showed me where the shroud had slid forward almost 1/16", and then yawed ever so slightly right. Enough that the shroud was touching the gas block. He put it all back together right, tight, and then used LocTite on the shroud screws. Said I'm good to go; expects the irons to be on from the get-go; and warned me I'll have to make a big adjustment on the Aimpoint. Said to take the dot to the irons once they are zero'd, and that should get me close.
Hindsight being 20/20, the very instant that rounds starting "flying" when I knew I was dead-on and with good trigger discipline, I should have stopped right there and taken him that gun. Running 75 HPBT (Miwall) through it, on a good day I can shoot sub 2" groups at 100 yards. At 50? Round after round up a rat's butt. It's not me, it's the gun. So that being my CQB gun, I use a 50/200 (MPBR) zero. Up until now, it has never failed me.
I have taken a vow to shoot my way back into "fighting shape"; joined the local range; and plan to shoot every other Saturday and/or Sunday after church. I figure it'll take me 3-6 months to get back to where I was, although I have no way to practice the other, sometimes more critical skills, that go along with good basic marksmanship. There's a nearby LE range that has a 180-degree shoot range with pop-ups, but I can only get there three, maybe four times a year. It is what it is. I just need to get back to being confident that I'll be a hard target if I ever am one. Heck, the last time we did Active Shooter training, a new deputy tripped over me on a center-fed door entry, spilling him and knocking me off my hostile in the hard corner. We had to stop and explain to him how important the little stuff like foot placement is when making a dynamic entry. You don't just roll through the door. It's a ballet. A deadly one.
It sucks getting old and grumpy. You're old, and you tend to be grumpy a lot. What I have, what I can do with it, and what I know pales in comparison to some of the folks on here. I try to keep it simple. AR's and 45's. Makes it easier to pile up ammo when you're only buying two calibers. And a .45 is a .45. Glock, RIA, Springfield (times two now). Once you learn how to control that "thump" a .45 gives you, you could shoot it from a potato gun. All that changes is the sights and the trigger.
Love VN, and this thread. Lotta gunpowder here. Fun to be a part of it.
Go Vols.