Well...she still sits...pretty much as my last post. Life happened and my fun money had to pay for a new HVAC system. I did get started back on it...
1) As it turns out, that 315 wasn't that much to overcome. Torque was never out of spec when tightening...but a little bit of background.
Searching the .net, I ran across an article(youtube, actually) where a LR shooter was discussing issues he was having with POI shift. This, as I recall, was all in prep for a shoot. As his barrel warmed up, the POI shifted consistently in a specific direction. Back to the bench, spec checks, back out to the range. As his barrel warmed up, POI shift again. He noted the shift was not the same direction as previous, though, but consistent in the same direction. Back to the bench, spec checks, installed shims in place of the crush washer. Back out to the range and again, POI shift.
So he used his "phone a friend" lifeline...and called one of his "expert" friends. The issue as explained was the torque involve with both the crush washer AND shims. I'm no metallurgist to refute any of this, but, results speak. The "expert" explained the dynamics of the stress put on the barrel by the torquing of the muzzle device "spacers" and the heating of the barrel. Informed the shooter, to "throw" the spacers over his left should with a dash of salt, get some thread locker(I think/assume it was blue), reinstall the muzzle device and time it. Back out to the range, no more POI shift.
I'm not sure I want to be running around in the woods with nothing but blue thread locker on my muzzle device. My solution(for now), to mitigate my concern about over torquing with the crush washer...baby steps. A little duct tape over the shoulders of my VG6 and a crow's foot wrench(I really hate adjustable wrenches) and here we go. Tighten a little, back it off, repeat until I'm "close"(1/8 turn or less maybe) to timing. The idea is to get to timing with least amount of torque on the barrel. Or, maybe a little custom work as Greg mentioned and have the back of the VG6 shaved...we'll see if my solution works or not, first.
Now, install rest of the upper before finishing the muzzle device.
2) Gas block and tube. I procured a new WC(Wilson Combat) gas block a friend had on hand and donated to me...what a pal. Had a stainless, rifle length tube in my parts box. But wait...gotta have that hand guard installed first.
3) Finally settled on a hand guard. Call me particular, but, I really, really wanted a "delta" form hand guard. For the AR308, I've found only a couple, outside of standard A2/M16 delta style. One is carbon fiber, pretty hideous I might add, and not cheap. The other I found is from Diamondhead Arms...not cheap either, just better. Specifically this
VRS-T model. Found a deal on it from Optics Planet and received it in the mail.
Nothing worse on Christmas morning than when your brand new train set that Santa brought you doesn't work. WHAT!? Yup...didn't work. Specifically, and perhaps rectifiable, the barrel nut wouldn't thread onto the upper. Uh-oh! Two possible issues as I determine. I could thread it only partially on the upper receiver, but not near far enough. OK, well...I can figure this out...to the parts box; but, nooooo...I didn't have a "standard" AR308 style barrel nut! Phone a friend and he lent me one. The "standard" barrel nut hand threaded snug and was ready for to torquing/timing. After a few calls, the hand guard assembly is flying back to OP(not Overland Park here in Kansas)...postage paid...great CS from Optics Planet. Essentially, the barrel nut in the kit from OP didn't match the threads on the Aero Precision M5 upper.
I see on the Diamondhead sight, they have multiple TPI barrel nuts(16 and 18)...go figure. I'm gonna guess, wildly, and say perhaps the difference is for forged vs. billet uppers...dunno. I'll have to ask that question...but, the guys at Diamondhead said they'll getting me going.
Now, it's a waiting game, again, to get the replacement. I need a little time on the bow range, anyhow. Season will be here soon.
4) Did I mention the glass...? Maybe so, but, I have it now. The deal hunter I am, I found a nice sale on a Burris AR-762 4.5-14x42mm I think will be all I need for hunting with this rig.
To be continued...
