Loose Barrel Extension

[StoneHendge]

Has anyone ever experienced or even heard of a barrel becoming loose in a barrel extension due to anything other than a barrel not being properly installed in the extension, or either the barrel's threads being out of spec or the extension being out of spec?

[montana]

I have never personally experienced this, but Chad from SOTAR has many times..It can happen if the extension was not torqued to the proper 150 ft pounds with a factory thread locker like Colt uses and when trying to remove a barrel nut that was over torqued or /with a thread locker that surpassed the barrel extension torque..I have heard this can also happen while removing an over tight muzzle device much like a barrel nut..

[LRRPF52]

If you torque off a muzzle device to remove it and the extension hasn’t been installed with more torque value, the barrel can separate from the extension.

There was a funny one where someone turned their gas tube into a spiral wrap around the barrel.

[StoneHendge]

Thanks guys. I can visualize this with a muzzle device, but if the barrel extension was torqued on properly to 150 fl lbs, it seems like it would take an awful lot of effort to torque the muzzle device enough to exceed 150. On the other hand, if the extension wasn't torqued down properly, it could certainly be something that could cause a barrel in an extension to loosen.

I'm having a hard time visualizing how it could occur with over torquing a barrel nut or using thread locker since the torque applied to the barrel nut would run through to the receiver (at least with my Wheeler vise block) before the barrel nut thread / upper receiver thread interface breaks free to turn.

Edit: I'll add that it seems to me that if the muzzle device was put on with torque greater than that of the barrel in the extension, the barrel should unscrew from the extension with the muzzle device remaining on the barrel.

[lazyengineer]

I have.

My direct factory purchased Alexander Arms did this to me. Drove me nuts trying to figure out why my groups would open up and drop 12" when warm. Tightened back up when cool. Finally was able to just spin it off barehanded. I bought the barrel as part of an Alexander Arms kit. It was then mounted via conventional vice block to maybe 50 ft-lb,no reaction rod. So no way was that due to the barrel mounting.

AA took it back, and fixed it. Yet my timing didn't change one bit, so not sure how they fixed it, without touquing the barrel extension farther, but it hasn't come loose again since.

[LRRPF52]

I don’t do any muzzle device work without the barrel being clamped in a vice using inserts. I never do muzzle device work that involves the upper receiver or any torque applied to the barrel extension. Some muzzle devices have been installed with Rocksett, so they aren’t going anywhere with just torque.

[Lemonaid]

After seeing this video (School of the American Rifle), I'm getting a Midwest Industries upper receiver rod, mostly for the ease of proper alignment of the barrel.

https://www.youtube.com/watch?v=7FemsC5JStw

[StoneHendge]

After seeing this video (School of the American Rifle), I'm getting a Midwest Industries upper receiver rod, mostly for the ease of proper alignment of the barrel.

https://www.youtube.com/watch?v=7FemsC5JStw

Does this explain how a barrel could become loose in an extension if the extension had been properly installed on a barrel?

[StoneHendge]

Question for those who have either installed barrel extensions or are familiar with their installation. How many degrees of rotation does it take to get a barrel extension from hand tight to 150 lbs of torque? Having installed a number of ALG handguards where the spacer / timing system gets it to 50 lbs, it's certainly several degrees from hand tight to proper torque. I ask this because in my situation, the bolt slides freely in and out of the chamber with the index pin aligned in the receiver, yet there is "play" between the barrel and the extension.

[Klem]

My understanding of MILSPEC barrel nut torque is anywhere between 30 and 80 Ft. Lbs. The range being the rotation required to align the next slot for the gas tube. MILSPEC barrel extensions have 20 raised teeth and 19 slots in a circle. That makes it 18.9 degrees of rotation between each slot (=360/19). No doubt as it tightens up past 80 Ft Lbs the degrees of rotation rapidly decreases.
barrel nut.jpg

Non-MILSPEC handguard manufacturers recommend their own settings. For example SLR Solo handguards are 35 Ft Lbs.

[montana]

If I'm understanding you correctly, you are saying your barrel extension is already loose..If it is, then it is time to get a new barrel or see if the manufacturer will warranty it.. The barrel extension should never come loose..

The problem with tightening a loose barrel extension to a proper 150ft ibs of torque while keeping the barrel gas port aligned with the barrel index pin and maintaining proper head space is very difficult....Chad from SOTAR claims he can do it, but it would cost a lot more to fix than purchasing a new barrel...I do know it is possible to install a new barrel extension and install a new index pin to match the barrel port, but how they do it is above my pay scale....

The main reason a barrel extension will come loose is improper installation of the barrel extension at the factory..It is also possible for a barrel extension to loosen by way over tightening (torquing) the barrel nut using a barrel vice..Even then I would suspect it was improperly installed at the factory..For a barrel extension to come loose, it would take way over 150lbs of torque to loosen..

What chad was mostly showing in the video is the amount of torque the barrel nut can impart between the index pin and upper receiver when using the wrong tool..This usually results in a broken index pin, broken upper receiver barrel threads or a clocked barrel..

[StoneHendge]

If I'm understanding you correctly, you are saying your barrel extension is already loose..If it is, then it is time to get a new barrel or see if the manufacturer will warranty it.. The barrel extension should never come loose..

The problem with tightening a loose barrel extension to a proper 150ft ibs of torque while keeping the barrel gas port aligned with the barrel index pin and maintaining proper head space is very difficult....Chad from SOTAR claims he can do it, but it would cost a lot more to fix than purchasing a new barrel...I do know it is possible to install a new barrel extension and install a new index pin to match the barrel port, but how they do it is above my pay scale....

The main reason a barrel extension will come loose is improper installation of the barrel extension at the factory..It is also possible for a barrel extension to loosen by way over tightening (torquing) the barrel nut using a barrel vice..Even then I would suspect it was improperly installed at the factory..For a barrel extension to come loose, it would take way over 150lbs of torque to loosen..

What chad was mostly showing in the video is the amount of torque the barrel nut can impart between the index pin and upper receiver when using the wrong tool..This usually results in a broken index pin, broken upper receiver barrel threads or a clocked barrel..

Yes, the barrel extension is already loose.

I first attempted to contact the vendor 17 days ago and have not received a response. I contacted the manufacturer a few days after I attempted to contact the vendor and with some prodding, I have received 2 responses from the manufacturer - both of which were rather quick "it must be something you have done" emails. Further attempts to explain what I have done with the barrel since I bought it over 90 days ago and the 2+ months I spent attempting to trouble shoot before I realized what the problem is have been unanswered. My frustration is evolving into anger as I have now not had a response from them for 9 days.

A few things I'll note:

- I use a Wheeler upper receiver vice block that secures the receiver to the block through the takedown pin holes. I also use a wheeler torque wrench. There's no way I ever got the barrel nut torque to 150 lbs (it's off of the scale) and even if I did, I can't see how that torque could be transferred to the barrel or extension with my block.

- I use a Wheeler AR-15 combo tool for muzzle device work. The handle is 9" from the from the point where the wrench interfaces with the compensator. If I put the full weight of my 185 lb body on the wrench, that would be 138.75 lb/ft of torque. There is simply no way that anything remotely close to 150 lbs of torque was put on the muzzle device.

- There is play between the barrel and the extension. I can't feel it holding the barrel in one hand and the extension in the other, but my body builder neighbor who is also much younger can. It is more back and forth and side to side, but there is a small amount that is rotational. Since it creates more leverage, the play can be felt by anyone when the barrel is installed in an upper receiver with both the barrel nut being hand tight and torqued down to 50 lbs. That play can be felt in 3 different receivers. There is no play when 2 other barrels are installed both hand tight and torqued to 50 lbs in all 3 receivers. The best description of the play is the slop feeling of a barrel and receiver held together by hand when it isn't a press fit.

It's purely a guess, but I am thinking that the barrel extension pin has been driven into the barrel threads and that is why there isn't really rotation from the loose extension - just the play. Either that, or there is significant damage to the threads on either the barrel or extension.

When the barrel is installed in the receiver, the gas port is in line and the bolt slides freely in and out of the chamber. And there is the "play".

What I am hoping for is some confirmation that this means it would have been virtually impossible for me to do anything that could have created this situation. If the extension had been torqued on properly and I loosened it somehow as the manufacturer is inferring, then the gas port should not be in line and the bolt should not be able to slide in and out of the chamber. It shouldn't even be close!

Then I'm going to make one last attempt to contact the parties involved. Thanks!

[montana]

If you have the barrel properly tightened in the upper and you can feel slop either rotational or forward and backwards, then the barrel needs to be sent back and the manufacturer should warranty it IMO..Blaming the user without any questioning on barrel installation technique or procedure says it all.. I would not let it go without a fight..

The threads on the barrel extension are a right hand thread..If the upper was secure but not the barrel, then it is possible to loosen the barrel extension by loosening a muzzle device that exceeds the 150lb torque.. There can be a lot of torque applied to the barrel/extension when trying to loosen a muzzle device that was applied with Rocksett, over torqued/carboned tight..

The opposite is possible if the barrel is secure and not the upper, if the barrel nut was tightened exceeding the 150lb torque.. The upper would need to spin with the barrel extension for the extension to come loose..

I don't see how your method of mounting a barrel could possibly loosen the barrel extension..Your method can be hard on the upper receiver, the barrel index pin and could also create a clocked barrel, but should not loosen the extension.

I think you are on the right track about the index pin and threads..It is possible to verify this by removing the index pin, but only if the manufacturer (will not) warranty the barrel..Manufacturers love to deny any warranty for the minimal alterations..

This shows how the barrel extension is installed on a barrel..

https://www.facebook.com/watch/?v=375029623412573

[StoneHendge]

If you have the barrel properly tightened in the upper and you can feel slop either rotational or forward and backwards, then the barrel needs to be sent back and the manufacturer should warranty it IMO..Blaming the user without any questioning on barrel installation technique or procedure says it all.. I would not let it go without a fight..

The threads on the barrel extension are a right hand thread..If the upper was secure but not the barrel, then it is possible to loosen the barrel extension by loosening a muzzle device that exceeds the 150lb torque.. There can be a lot of torque applied to the barrel/extension when trying to loosen a muzzle device that was applied with Rocksett, over torqued/carboned tight..

The opposite is possible if the barrel is secure and not the upper, if the barrel nut was tightened exceeding the 150lb torque.. The upper would need to spin with the barrel extension for the extension to come loose..

I don't see how your method of mounting a barrel could possibly loosen the barrel extension..Your method can be hard on the upper receiver, the barrel index pin and could also create a clocked barrel, but should not loosen the extension.

I think you are on the right track about the index pin and threads..It is possible to verify this by removing the index pin, but only if the manufacturer (will not) warranty the barrel..Manufacturers love to deny any warranty for the minimal alterations.
This shows how the barrel extension is installed on a barrel..

https://www.facebook.com/watch/?v=375029623412573

Thanks Montana. Yeah I'm going to keep at them. I'll also note that I never use Rocksett on a muzzle device and this barrel only had about 40 shots on it when I removed the muzzle device the first time because I had felt the barrel moving and accuracy had moved from being quite stellar to shotgun groups. I had originally misinterpreted the play for a faulty barrel installation and later on the upper receiver. Regardless, if I had in fact loosened the barrel from the extension through an over torqued muzzle device, the gas port should not be aligned with the retaining pin and the bolt should be nowhere close to sliding freely in an out of the chamber.

[StoneHendge]

The level of arrogance is really quite stunning, but I appear to have struck a nerve and after 3 weeks have finally made some progress and will be sending it on

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Morning Stone,

Again, those extensions are torqued at 150ft lbs. The extension pin is then pressed in after that process. Like I said in my previous email, something serious must have happened on your end of that to have come loose. This is not, as you put it, “Clearly a defective product.”

I’m more than happy to help you with your issue, and take a look at your barrel. But trying to put blame on a defective product is just not the way to do it.

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Sounds like the extension pin is likely holding the barrel in the extension resulting in play but not rotation.

I honestly can't think of any other industry where you could hang your shingle on the high end and get away with taking a position like this with your customers.