Going to try the “precision” game and just replacing barrel on a existing upper that I have (BCM). I’m curious as to any tips to squeeze extra accuracy out of the rifle example would be bedding gas block, bedding (placing red loctie around the barrel extention), truing up the front of the receiver where the barrel nut threads are and etc.
Thanks!
Try to avoid excessive torque on the barrel nut. According to Grant and some of the other M4C moderators/regulars, the ideal torque range is 35-45 ft. lbs.
Barrel nut torqued at the lower end of the torque range.
Everything you mentioned plus a matched headspaced bolt at the minimum end of the spec range.
You can skip on the matched bolt, but in my experience the rifle will be more accurate with a wider range of different loads. If you’re only shooting fire formed brass that you are shoulder bumping, it won’t matter.
A heavy(er) profile QUALITY barrel with a good chamber is paramount.
As said above, avoid excessive torque on the barrel nut AND the muzzle device. Just avoid putting too much stress on the barrel in any way possible.
I rec the precision armament muzzle shim set to keep muzzle device torque low.
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If your going to bed the barrel use loctite 609. It is specifically designed for this type of application. IIRC it is called a sleeve retainer.
Check upper reciever for sqare(front). Bed barrel as above. Quality pieces and pay attention to torque specs.
Thanks everyone!
What would the difference been in 609 and 638 as I’ve seen both mention.
To bed it just put a coat of loctie around the barrel ext. then slide the barrel in to the receiver. Next, wipe up excessive while supporting the barrel so it doesn’t move. Attach barrel nut and tq it down. Is this the correct steps?
I have a book that tells how to match a bolt to the barrel with the correct specs. But can’t remember, I’ll try to find that here.
Ammo I’m shooting is some 62 grain CBS Magtech (5.56) Heard great things about it, so I want to try it. Parts come in Tuesday.
I also picked up a barrel extension tool to tq the barrel nut down. Same one that geissele sales but it’s brownells and some vice padded jaws. I prefer to clamp as close to the muzzle as I can when installing muzzle device. Mine the AAC blackout 2.0 doesn’t needed timing or shims (suppressed) so 20 ft-lbs will be good? Using a syrac gas block.
You really don’t need any of this stuff. Get good components (barrel, rail and trigger) and couple that with good ammo. Most people cannot shoot the potential of their rifles and they often times short change themselves by using crappy ammo and optics.
All of these “precision” steps won’t make the slightest difference if you’re using crap ammo.
Good components are key. Here are the little extra’s I do to my guns:
Good luck!
C4
This the ammo I stock pile. I want to see what it will do with this ammo, then I’ll build a load for it.
Thanks Grant! All I know how to do but fitting the bolt to the extension.
Edit: Seems like the only thing one can do when fitting a bolt is have a few bolts and see which one fits the tightest in the barrel extension. Sounds like I need to buy some extra bolts, as I only have two. Since I only have 2 complete Ar’s.
https://www.m4carbine.net/showthread.php?116845-Fitting-a-bolt-to-a-barrel
Do you have the correct gauges and the range on the bolt to barrel ext fit? If not, you really aren’t fitting the bolt.
Controlling the barrel nut weight just means that you use either a BCM or Geissele rail OR buy the Geissele shims so you can time nut. You will also need a calibrated torque wrench. Same for for the FH/MB.
You can send your barrel to us and we will square it and put an 11 degree crown on it for you. Cost is $30.
C4
This. If you have a good barrel, the next area of focus is on the Ammo.
Grant,
I only have a set of go/no go gauges. I’m looking more in to this and digging up as much as I can, I’m really curious how this is done now and the science behind it. I did order the shim just in case as I did read about that on here from one of your older post. 
What the turn around time on the barrel normally?
Thanks!
Those gauges won’t do anything towards fitting a bolt.
Turn around is usually 3-5 days.
C4
Awesome!
Would you need a match set of gauges or a totally different total different type?
http://www.midwayusa.com/product/549020/forster-complete-match-headspace-gage-set-223-remington
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Those are the gauges needed to fit a bolt. 1.4646 is the money one IIRC.
That ammo is probably every bit as good, if not better than U.S made. But, it’s not match ammo.