AR Barrel install?

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TrxR

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When installing a barrel do you a little grease on the barrel extension where it slides into the upper as well as a little on the barrel nut threads? I have Aeroshell grease.

Also I seen somwhere about seating it by torquing to around 30ftlbs and loosening it off a few times before going to 50ftlbs.?

Anything else that should be installed into the upper before the barrel? Will be using a torque rod for this if it makes any difference.

Thanks
 
That sounds about right for your process.
the full 50ft lbs is a lot and applying it all at once...particularly on a new receiver/barrel is not wise.
Running it up a few times to the full spec is prudent.
Personally I think 50ft lbs is unnecessary and a lil too tight....anything better than 30ft lbs should suffice.

I wouldn't go crazy with lube...and I wouldn't use lube...I would use a whisper of antiseize or similar product.
Excessive lube occupies space and that compounds the torque applied. Just enough antiseize or grease on the threads to prevent galling and allow the thread to mate easily is enough...and prevent corrosion of course.

my 2c worth
 
Between 30-80 ft/lbs is within spec, and use the backoff method as it helps get the grease into the threads as well as makes sure the torque value is accurate. You need to line up the barrel nut tines so the gas tube does not touch the tines or upper reciever, so your torque will vary depending on alignment. Aeroshell grease is the milspec option, it’s what I use. It will prevent galling/corrosion with aluminum and also provide the right lubrication for the torque specs. Anti-seize works but depending on the type may not prevent galling and may not be the proper viscosity as a thread lube. I’ve always used aeroshell so I’ve only read about issues with anti-sieze and haven’t had personal experience with it.

I find it easier to install the ejection port and forward assist before installing the barrel, but that’s more person preference.
 
The forward assist and port door is already installed. As for the gas tube alignment, that a non issue as this is a Aero m4e1 enhanced with the internal barrel nut . I understand that aeroshell grease kind of acts as an antiseaze as well.

Thanks
 
Kratos said:
Between 30-80 ft/lbs is within spec, and use the backoff method as it helps get the grease into the threads as well as makes sure the torque value is accurate. You need to line up the barrel nut tines so the gas tube does not touch the tines or upper reciever, so your torque will vary depending on alignment. Aeroshell grease is the milspec option, it’s what I use. It will prevent galling/corrosion with aluminum and also provide the right lubrication for the torque specs. Anti-seize works but depending on the type may not prevent galling and may not be the proper viscosity as a thread lube. I’ve always used aeroshell so I’ve only read about issues with anti-sieze and haven’t had personal experience with it.
Click to expand...

This post is 100% correct. Copper-based anti-seize isn't good to use with aluminum like what your upper is made out of because it may develop corrosion issues (copper and aluminum = no no). Moly grease is the best and is the recommended grease to use.
 
I came across a couple good videos from Joe Carlos going over precision ar builds. He recommended shimming the barrel extension with shim stock or green loctite to take out any play perpendicular to the barrel. He explains it well. Either way I don’t think I’d be too inclined to grease up the barrel extension. Definitely aero shell on the threads though.

https://m.youtube.com/watch?v=pJL-IscH_jo
 
What torque do you all recomend for final torque? Aero lists 50ftlbs in there instructions . Should I set it at 45 or so?

I just installed a Geiselle SD-E trigger in it and made an order for a 19" barrel from IBI barrels so I got a bit of a wait but am making sure of what I need to do when I get it.

Thanks
 
TrxR said:
What torque do you all recomend for final torque? Aero lists 50ftlbs in there instructions . Should I set it at 45 or so?

I just installed a Geiselle SD-E trigger in it and made an order for a 19" barrel from IBI barrels so I got a bit of a wait but am making sure of what I need to do when I get it.

Thanks
Click to expand...

No Less than 30 ft.lb.
 
gcoy19 said:
I came across a couple good videos from Joe Carlos going over precision ar builds. He recommended shimming the barrel extension with shim stock or green loctite to take out any play perpendicular to the barrel. He explains it well. Either way I don’t think I’d be too inclined to grease up the barrel extension. Definitely aero shell on the threads though.

https://m.youtube.com/watch?v=pJL-IscH_jo
Click to expand...

I think one of us is missing the question the OP put forth.
Greasing the barrel extension is not a good plan. Shimming should not be required, assuming the barrel extension fits snugly into the upper. many "milspec" uppers are loose fitting so shimming would be of benefit. On any of the high quality uppers, they should not require the shimming.
On ALL Ar uppers moly grease should be applied to the threads of the barrel nut to create a barrier between the aluminum upper and the steel barrel retaining nut to prevent galvanic action from occurring. Dissimilar metals, especially aluminum and steel create a corrosion unless there is some barrier between the 2 metals. True anodizing of the upper "should" prevent this just as nitriding of the barrel retaining nut "should" however grease will prevent this corrosion completely.
 
I just did my first one, torqued to 50 ft lbs. It seemed like a lot of torque.. :)

Also ,be careful of those crush washers on the brake.
I had to dermal about 20 cuts into it, before I could break it off.

There was no way it was just sliding off.
 
alberta tactical rifle said:
I think one of us is missing the question the OP put forth.
Greasing the barrel extension is not a good plan. Shimming should not be required, assuming the barrel extension fits snugly into the upper. many "milspec" uppers are loose fitting so shimming would be of benefit. On any of the high quality uppers, they should not require the shimming.
On ALL Ar uppers moly grease should be applied to the threads of the barrel nut to create a barrier between the aluminum upper and the steel barrel retaining nut to prevent galvanic action from occurring. Dissimilar metals, especially aluminum and steel create a corrosion unless there is some barrier between the 2 metals. True anodizing of the upper "should" prevent this just as nitriding of the barrel retaining nut "should" however grease will prevent this corrosion completely.
Click to expand...

Op asked if he should grease up the extension as well as the threads. I suggested not to grease the extension and if it’s loose fitting possibly shim it as per the video. What am I missing?
 
I use Dow Molykote GN assembly paste instead of grease. I also bed the barrel into the upper with Loctite 515 flange sealant. I doubt you could ever get enough grease in or on the parts to interfere with assembly. Back when I was lucky enough to assemble some DMR rifles under the watchful eye of an AMU armourer the GN was applied with a 2" paint brush and in no small quantity.
 
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