Post by ChiefPlumber on Feb 23, 2018 15:42:54 GMT -8
OK...so it's really on the way now. Just got the shipping notice. Not complaining, but I was getting a little itchy to get it done what with the time I have to put it together waiting for this Kansas ice to thaw. Need to get down to AR and help my buddy with some hogs...they got his red healer back before Christmas.
You could use a timing shim set to get the muzzle device timed with a minimum amount of torque. I converted all of my rifles from crush washers to shim-timed to a "slight wrench snug up just past hand tight" - this combined with red loctite. It's a subject of debate - that crush washers can degrade accuracy a bit... and that a normal or heavy torquing of the muzzle threads can cause POI shifts as the barrel warms. I will only go so far as to say that I have seen some improved groups in a few of my builds after shimming with light torque, and no poor performance from any I've built this way... helped with some, but didn't hurt any. And it's very easy to do.
Post by ChiefPlumber on Mar 2, 2018 17:32:31 GMT -8
Yup. I was reading a little on that very thing. Not that this break will take a can...but if I were to go that route, I see shimming is the thing. I hand threaded the brake on and when in timed position, it won't take a pop tab in the gap. So I think I may just get me a shim kit.
Post by ChiefPlumber on Aug 21, 2018 16:40:11 GMT -8
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.
Post by ChiefPlumber on Sept 19, 2018 18:16:41 GMT -8
...and here she is!
Lesson learned: crush washers suck! I did the baby steps to get the timing and didn't like the outcome. To make things worse, after crush, it wouldn't slip back over threads as it had been deformed. It took a good pair of side cutters and several choice words to break the washer without mucking anything else. What a monumental waste of time to learn my lesson. 2 shims and the muzzle device is in place.
Anybody have tips for A2-style stocks? I'd like to just throw it up and be in position...kinda like a kisser button on a bow string. I need to find my anchor point and get the glass in the correct position so I can set the focus without eye correction. I don't were glasses full time...just cheaters...or have my brother make me some lenses with correction in one eye.
Speaking of eyewear...You folks that live in the Phoenix area go see Robert(my brother) at Decot Hy-Wyd(deco high wide). Custom shooting glasses are what they do. They'll tweak your script for your shooting...if needed...add tint, UV...or no script, whatever. I won't drop names...but there are many well knowns. If you're not in Phoenix, here's there show schedule. Robert can also set you up with custom ear protection as well...solid, filtered, or with sound drivers.
Load development and chrono
Send off for custom turret based on chrono and load