Accurizing AR barrel install ? Is there such a thing ??

You shim the joint between the barrel extension and the receiver with round shims specifically made for the job.
There are many places that sell them, and even a few different versions. This is just one example: Bison Armory AR-15 shim set

Each of those shims effectively adds 0.001" to the length of the barrel boss on the upper receiver, which stops your barrel nut slightly more than 1/3 of a notch/hole short of where it torqued without the shim. It lets you achieve alignment for the gas tube, with the torque setting you want to use. ....Or it lets you get a proper torque value with barrel nut - barrel extension - upper receiver combinations that are just stubborn and won't align otherwise.
 
What about the slight wobble the barrel has is the reciever before the barrel nut is on . That has been what I've been talking about this hole time . I understood the lapping and shims for the torque . oops guess i never really said that , sorry
 
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I really don't think filling the gap between the barrel extension and the bore of the barrel nut boss makes much of a difference ...especially with a barrel of average or mediocre quality. (I don't' remember what you said you were using, but I believe you said it was nothing special. Please correct me, if I'm wrong.)

If I was going to do it, I'd have a hard time deciding between Loctite 222 (purple / low strength) and Loctite 243 (blue / medium strength / oil resistant). The 243 would hold up better long-term, but it would also require heat to remove the barrel - should the need arise.

Or just having BAT Machine punch out one of their custom oversized barrel extensions.... ;)

I wouldn't consider, even for a moment, using one of the sleeve retaining compounds. A lot of heat is required to remove parts installed with that stuff (even the "low heat" 620), so I'd consider that installation to be permanent. ...Better hope it works the first time. :eek:
 
I just finished putting it together with nothing between the barrel extension and the receiver pocket . I'll see how it shoots on Saturday .

The barrel is a AR-stoner from midway USA . I believe ER-Shaw makes them so it's not just any barrel . 20" HBAR 1-8 twist 5r rifling . I have a national match free float sleeve from rock river . Giesslie service rifle trigger so the rifle should be pretty nice . This rifle will be for shooting NRA high power service rifle competition . That means I'll be using iron sight almost exclusively but will through a scope on it at some point just to see how good it really can shoot .
 
The reason a thermal fit works best is because the aluminum and steel have different rates of thermal expansion. Also, unless the aluminum and steel are "perfect" (which is not possible BTW) there will be some very small dimensional changes within the parts themselves. These small changes and expansion rates result in the axis of the bore moving in relation to the axis of the top rail, where the optic or rear sight is presumably mounted. I have played around with some where the Irons, with a barrel mounted front sight, held a tighter group than a receiver mounted optic. RTV does not have the strength to resist this movement.

LocTite creates a bond due to corrosion, and the aluminum stainless corrosion cell needs no water to become active.

I tried the AR-Stoner barrels, and frankly, they are middle of the road barrels, nothing spectacular. Some needed to have significant polishing and the chamber casts revealed several machining marks beyond what I would consider acceptable. With Irons and the barrel you are using, this whole discussion is probably not something you should concern yourself with too much.
 
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