Removing AR-15 Factory Barrel Nut

Midnight412

Midnight412

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I have a BushMaster XM15-E2S that I am taking down to install a free float Quad Rail. I have the AR wrench, but I cannot budge the barrel nut at all. I have tried quite a bit of force and am worried to break something.

I assume there must be some thread locker on the nut, so I just sprayed some PB Blaster there to soak a few minutes while I post this.

What is normally used to get the factory barrel nut to break free? Heat with torch, penatrating lube, etc?

Thanks!
 
I don't have a vice block. it's a flat top, so I have the receiver turned sideways in the vice, gripping it from the top and bottom of the receiver sandwiched between two pieces of soft wood. It seems to hold very well, but I don't want to have to put excessive force to turn the nut.
 
Well some barrels do take quite a bit of force. If the factory didn't grease everything up well then it's going to be even tougher (I wouldn't suspect that from Bushmaster). Can you gain access to a vice block? I can let you borrow mine, but I'm in the 495/90 area. I do know someone from work that may be able to swing by after work this week with it since he lives in Gardner as well (he's a gun person too).
 
jrbtzx12r

Thanks for the offer. I'm going back to try again. If I can't get it loose now, I would very much appreciate borrowing a vice block. I'll PM you later if I am stuck and we can try to arrange something.
 
I think the torque specs for an AR barrel are 35-80 ft/lbs. I have found that it's not usual to get above 50-55 ft/lbs when torquing a barrel down so a factory barrel should come off pretty easily unless they screwed it up somehow. I'd recommend holding off for a vice block so you don't mess that upper up.

Also it's common to apply some type of anti-galling lubricant to the upper receiver when attaching the barrel but i've never heard of anyone using threadlock to keep it all together.
 
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WOW

That was on tight. It finally let go after the PB Blaster and a bit of heat from my propane torch on low flame setting. Even with that it felt like I was about to pick the wokbench off the floor. As soon as it broke free, I was able to spin it off by hand.

Now the new UTG free float quad rail is installed. Sweet.
 
Midnight412 said:
WOW

That was on tight. It finally let go after the PB Blaster and a bit of heat from my propane torch on low flame setting. Even with that it felt like I was about to pick the wokbench off the floor. As soon as it broke free, I was able to spin it off by hand.

Now the new UTG free float quad rail is installed. Sweet.
Click to expand...

More toys today? Cool!
I cant wait to see what you picked up!
 
I found with the upper vice block in a very good vice, and a secured bench they come off easy. the first one I did was with blocks of wood small vice and those home depot benches
 
When you put it back together, the TM calls for moly grease. Just make sure your moly grease dose not contain graphite though. Aluminum and graphite don't mix well together.

B
 
Get to Home Depot and buy some Anti Sieze compound, put that on the threads of the nut. It will allow you to tighten the barrel nut much smoother. A National Guard Marksmanship Unit armorer told me about that, it's never failed to work as he said, regardless of firearm or action tiype.
 
bpm990d said:
Dan,

Just FYI, all the Permatex anti-seize stuff I have been able to get at the local stores has graphite in it.

B
Click to expand...
What is the issue with the graphite? Does it affect an anodized part?
I'll have to look at the stuff I have. I've had it for about 15 years....still have 20 years worth left.
 
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abomb60 said:
I think the torque specs for an AR barrel are 35-80 ft/lbs. I have found that it's not usual to get above 50-55 ft/lbs when torquing a barrel down so a factory barrel should come off pretty easily unless they screwed it up somehow. I'd recommend holding off for a vice block so you don't mess that upper up.

Also it's common to apply some type of anti-galling lubricant to the upper receiver when attaching the barrel but i've never heard of anyone using threadlock to keep it all together.
Click to expand...


The last barrel I installed went to just about 80ftlbs to get the proper alignment. Sounds like it worked out for the guy but echoing what you said a upper reciever vice block and a good solidly mounted bench vise is, I think vital to a proper assembly. I use a little hi-temp wheel bearing grease on the threads.
 
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From the PM magazine. It will promote galvanic corrosion. Although I completely disregard their prohibitions on motor oil. :-)

graphiteu.jpg


B
 

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