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I have my own methods but it's always important to reassess from time to time as products and idiologies evolve. What do you use and the reasoning behind it?

I've seen some barrel mfg's recommending 609. 620 has better heat resistance, although not bullet proof. JB having the absolute heat resistance. Shimming is more complicated, although, likely has the greatest impact on groupings. And in the "none" category... lapping is sufficient and benefits of bedding are too marginal to matter.

What say you?
 
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None. Unless this is a competition rig, then I’d say everything.

E7CD58CE-5CBC-4666-A271-705D7FB23D29.jpeg
 
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I take it most folks don't bed their AR barrels, haven't experimented with different methods/products or simply feel whatever you use isn't critical enough to warrant discussion(?)

:s0092:
 
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Having shot long distance I understand action bedding, but why bed the barrel? I thought that the whole idea was to free float the pipe clear back to just forward of the recoil lug.

Feel free to educate me; as I'm not familiar with this.
 
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Having shot long distance I understand action bedding, but why bed the barrel? I thought that the whole idea was to free float the pipe clear back to just forward of the recoil lug.

Feel free to educate me; as I'm not familiar with this.
Yup. In an AR it's bedding the barrel extension to the inside of the upper receiver. The length of the barrel remains free floating.
 
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Is there real world benefits to bedding a barrel with the AR platform? I can see it may make future barrel removal near impossible but, upper receivers aren’t too expensive.
 
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Is there real world benefits to bedding a barrel with the AR platform? I can see it may make future barrel removal near impossible but, upper receivers aren’t too expensive.
Personally, I dunno. I've always done it and haven't experiemented with/without on a single platform. The prevailing information though suggests that lapping and bedding your barrel can decrease MOA by up to a 1/4. It seems to make sense that mating the barrel as soundly as possible to the upper might be beneficial.

I always figured... it's only 1 additional step with the most minimal of effort... swipe a finger on it and you're done (other than heat shimming)... so why not?

Personally, I've only ever used 620... and I've swapped barrels before without too much effort. A bit of heat and it comes back out easy enough. Of course, I've taken barrels off pre-assembled uppers that aren't bedded and some still needed a bit of heat anyway so.... not that big a deal with or without, IMO.

I've "heard" thatJB weld is better because of the superior heat resistance. 620 is only something like 450. For a typical casual shooter you're not likely to go much hotter(?), but it's possible(?) Common(?). I've never put a heat gun on my AR's to check. JB though takes a tremendous amount of heat to break the hold that I'm not comfortable with. I would consider that only as a permanent option.

I've seen some barrel mfg's though suggestiong 609. Heat resistance with that is 300... so considerably less than 620 and much more easily reachable without too much real heavy shooting(?). Again, I dunno. It got me to wonder why mfg's would recommend it vs 620 though.

I couldn't find any previous discussion on it so... here we are! ;)
 
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I believe BCM uses 620 on the gas block.

I use 609 all the time at work for engine work.
I'd use 620 on barrel stuff.

It may not hurt and doesn't take long to do but for myself I'd need to burn out a few barrels and get to be a better shot than I am now to be be able to see a difference.

The only upper that I needed to face off was a cheap PSA 9mm upper.
I had to crank the windage all the way to the left on a red dot and iron sights.
Faced it off and it came back to center.
 
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The only upper that I needed to face off was a cheap PSA 9mm upper.
I had to crank the windage all the way to the left on a red dot and iron sights.
Faced it off and it came back to center.
Yeah. Lapping is a no-brainer. I learned that lesson a long time ago myself. Any pre-assembled... first order of business... tear them all the way down, inspect, measure and fine tune during reasssembly.
 
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Put me in the camp that says buy a quality upper that fits tight to begin with, lap it in and torque less than 40 ft/lbs using quality barrel nut/handguard. I never use anything but aeroshell on the threads. Can this be improved upon? Maybe, but I like being able to easily disassemble later and I am not sure my shooting skills could take advantage of a more accurate method.
 
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If you're building a rifle that gets hot enough to need 620, precision usually isn't its primary purpose. Either Loctite will work, but have different fixture time. Shimming isn't that hard to do and TriggeShims has shim stock variety packs of various thicknesses for fairly cheap. Joe Carlos started bedding National Match rifles many years ago and has some articles and videos on improved precision. He shims and uses Loctite. Never have done JB, I always figured that you can never re-barrel with that method. One of Joe's videos:
 
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If you're building a rifle that gets hot enough to need 620, precision usually isn't its primary purpose.
I would agree with that, but at least for mine, they aren't "either or" precision vs. mag dumpers. Precision when it's appropriate with the ability to do rapid or suppression fire without it affecting the precision fire capability. If I had one solely for precision and competitive shooting I would be more inclined to go to the work to shim fit a barrel, but competitive shooting has no appeal to me.

I prefer a "jack of all trades" to provide myself with as many options as possible.
 

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