Tightening ar-10 barrel extension

[tangolima]

The extension somehow comes slightly loose. I can feel wobble and see the barrel shoulder moves when I wiggle the muzzle. Have called the manufacturer for warranty repair. I reckon it will take weeks or even months before the rifle runs again.

That makes me contemplate doing it myself. The proper barrel extension wrench is out-of-stock everywhere I have looked. But this one is available.

https://www.brownells.com/tools-clea...-torque-tools/

I know it is not made for torquing the extension, but I think it should work. Plan is to hold down the barrel in a barrel vise and torque the extension with the tool and torque wrench. What think you?

Do I need to extract the index pin before I torque? I just pull it out with pliers?

Thanks for your inputs.

-TL

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[44caliberkid]

Is it the barrel extension that is loose, or the barrel nut? That tool is for tightening the barrel nut.

[44 AMP]

I think you need to wait for the maker to respond, and then send them the upper for inspection / repair.

IF things have come loose due to a defect in material or manufacturing, the maker needs to know about it.

The barrel extension (the part with the locking lug recesses) is supposed to be a permanent part of the barrel. Its not supposed to come loose, and IF it has, that is a serious failure, not something to just "tighten up" and go on.

Also, the tool you show is not made to do that, anyway. That tool is made to be used ALONG WITH the barrel nut wrench to tighten the barrel NUT, not the barrel extension.

You really need to have the maker inspect your barrel and its installation in your upper receiver.

Consider how the barrel is fitted in the upper receiver. It slips in, and is held in place with the barrel nut screwed onto the upper, trapping the flange on the barrel between them. You issue might be the barrel extension, or it might be the barrel nut, or even the upper receiver, or possibly a combination of two or all three.

The barrel isn't supposed to wiggle. The people who made it are the ones to find out what happened and fix it. Waiting is frustrating, but I think that's what you need to do.

[HiBC]

Various MFGRs have different ideas.
I bought a highly regarded match barrel for an AR-15 and used a GI or Colt Armorer's manual and the exact recommended tools to assemble.

Which included vise jaws milled to match the barrel diameter and a barrel nut wrench.
In my case the spec'd torque to tighten the barrel nut was sufficient to unscrew the barrel extension.
I learned a lot and so did the barrel outfit. They treated me right. There was no integrity problem.
Had the barrel extension and the barrel been assembled per the GI process, I don't think it would have come loose. As it was a commercial match barrel,these guys did things different in the pursuit of accuracy.
Without getting too detailed,they went with lower torque Ext to bbl on the theory that a less stressed assembly would be more accurate. I do not claim to know.
They also had an internal screw up where the wrong grade of LocTite was used on the threads.
We got it worked out.
The barrel vise jaws were part of the problem. I bought the Brownell's tool that goes into the upper like a BCG and engages the locking lug recesses in the BBL EXT. so the torque is transmitted to the extension vs unscrewing the extension from the bbl. That worked.
Before I received a new barrel,no charge, I explored re-torquing bbl # 1.

I went to the trouble of setting up on a surface plate and putting a gauge pin in the gas port to re-establish indexing. I used my height gauge to scribe little witness lines.
When I reassembled to the witness lines,torque was a few inch pounds,not much more than hand tight.
Options? I could use a tool similar to a knurling tool with no serrations to roll some metal up at the corner of the breech end of the barrel. That would get me some metal to crush against. (Yes,I'd take a minimal truing cut)
Or I could use a shim.

But Doggone! I spent a premium price for a cut rifled top end match grade barrel and it didn;t seem right I needed to blacksmith or shim it! And LocTite did not seem like the answer.

The barrel guys Fedex'd me a new barrel 2nd day and no charge ,no delay.

Stuff happens! They stepped up! No heartburn.

Warranty is certainty your best bet.

I've never had any luck pulling a blind dowel pin. Sounds futile. I can't document it,but I was told once the extension is assembled/torqued to the barrel,the dowel is actually driven into the barrel threads and stakes the assembly "permanently" Supposedly thats GI style.

My barrel guys didn't do that. They said it distorts the chamber.

I don't know.

What I do know is I now use tools that don't try to unscrew the bbl ext when I tighten the bbl nut, (I ditched vise jaws clamping the barrel)

[tangolima]

HiBC. Sounds like you were using the same torquing tool as in my link. I think it should work, except that its longer shank has more flex under torque.

My barrel is a cheap product from a bottom-of-barrel manufacturer. I suspect they didn't torque the extension tight either, but to rely on thread locker, to save cost. Quite possibly I broke the lock when I took the muzzle device off.

I certainly will wait for them to respond. I'm just contemplating alternatives. I probably will try torquing it myself if they just glue it back on.

The pin could be sticky. I may be limit how much I can tighten. I will see about that. Some say it pulls right out (I doubt it) and some say I have to drill it out. I don't really worry about indexing with the gas port. +/-5 degrees no problem. Ok to replace the index pin with set screw?

-TL

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[HiBC]

The pin could be sticky. I may be limit how much I can tighten. I will see about that. Some say it pulls right out (I doubt it) and some say I have to drill it out. I don't really worry about indexing with the gas port. +/-5 degrees no problem. Ok to replace the index pin with set screw?

I'm not a smith or an armorer. I would expect the dowel pin to be surface hardened quite hard. I won't say it CAN"T be drilled out. Folks in the machine trades have often found a way to do the impossible. For myself, I think I would create more problems.

I would not go with drill and tap either.

When I look at the cost and effort to build a rifle,for myself, a "bargain" barrel is a crap shoot. You might get one that works out. Or not.
They might invest a lot in the happy customer, or not. I'd ask for a return authorization and a refund. I spent near $400 for the barrel I had trouble with. When I called them to ask about it, without hesitation they said "Send it back, I'll get a replacement shipped immediately."



An AR parts outfit I was looking at is selling "Roscoe" brand barrels for $79.
Hmmm. Not me. Often buying cheap means buying again,

Outfits like Brownells and Midway sell there cheap lines.If,when you order, they commit to standing behind the product, (ASK! IMO,they will take care of their own reputation.If they get a bum vendor shipping junk, you will see "Product Discontinued"

Aero has never disappointed me. I know nothing about Faxon but Primary Arms is selling some for under $150

[MarkCO]

The barrel extension (the part with the locking lug recesses) is supposed to be a permanent part of the barrel. Its not supposed to come loose, and IF it has, that is a serious failure, not something to just "tighten up" and go on.

Correct. And you may have alignment issues as well. Locator pin and gas port.

I suspect you have a melonited barrel or it just was not built correctly.

[tangolima]

The manufacturer has sent RMA to return the barrel. So we will see.

Thanks guys.

-TL

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[stagpanther]

The barrel extension (the part with the locking lug recesses) is supposed to be a permanent part of the barrel. Its not supposed to come loose, and IF it has, that is a serious failure, not something to just "tighten up" and go on.

^^^^^^this^^^^^^