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Posted: 12/30/2011 3:11:09 PM EDT
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I am prepping my AR to install my newly ordered YH FF rail. Stag 2H upper
FSB off no issue. Compress the nut and got the hand guard off. Gas tube... off Now the barrel....I have the gun in the vise with the block...have the wrench.. the nut wont budge,,, tapped wrench lightly with a hammer... nothing.. dont wont to break anything,,,, thought these were suppose to be 30-40 ft lbs... 
help....? ANy ideas...? |
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Barrel nut spec allows up to 80 ft/lbs. Lefty loosey.
One little trick that might help is putting the upper in the freezer overnight before wrenching on it. Aluminum has a greater coefficient of thermal expansion/contraction than does steel, so lowering the temp will tend to contract the aluminum receiver away from the steel barrel nut, loosening the fit. That's assuming it doesn't have loctite on it or something like that. |
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Are you holding it with a BARREL vise block? In that case just put the whole upper in the freezer for about 30 minutes; the different thermal characteristics of steel and aluminum should help you out a bit. Then, making sure your barrel nut wrench grabs plenty of teeth, just put a long cheater on the wrench and carefully apply more and more force. Eventually the nut will slip.
I am prepping my AR to install my newly ordered YH FF rail. Stag 2H upper FSB off no issue. Compress the nut and got the hand guard off. Gas tube... off Now the barrel....I have the gun in the vise with the block...have the wrench.. the nut wont budge,,, tapped wrench lightly with a hammer... nothing.. dont wont to break anything,,,, thought these were suppose to be 30-40 ft lbs...
help....? ANy ideas...? While the assembly torque spec is "up to 80 ft-lbs," after the rifle has been assembled for a while, and especially after it's had plenty of rounds through it, you're not going to see anything like that torque - the parts settle into each other very thoroughly and you'll have to break their connection loose before the torque is a factor. This is why you MUST use a barrel vise block to remove a barrel; with an upper vise block, you may easily twist the front of the upper out of true. |
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Should I use a barrel clamp on block or will a upper rec block work ok as well...??  Barrel vise block ONLY. The problems that come from using a receiver block of any kind include twisting or even breaking the upper receiver, particularly when your barrel nut isn't cooperating. |
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Should I use a barrel clamp on block or will a upper rec block work ok as well...?? Barrel vise block ONLY. The problems that come from using a receiver block of any kind include twisting or even breaking the upper receiver, particularly when your barrel nut isn't cooperating. Wow. This is completely backwards. Get a Peace River receiver block, use the internal support, you're not going to break the upper. Just discussed this earlier in the week http://www.ar15.com/forums/t_3_4/557269_Barrel_removal_.html&page=1 |
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Should I use a barrel clamp on block or will a upper rec block work ok as well...?? Barrel vise block ONLY. The problems that come from using a receiver block of any kind include twisting or even breaking the upper receiver, particularly when your barrel nut isn't cooperating. Wow. This is completely backwards. Get a Peace River receiver block, use the internal support, you're not going to break the upper. Just discussed this earlier in the week http://www.ar15.com/forums/t_3_4/557269_Barrel_removal_.html&page=1 Just what I ordered today !! 
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GOT IT!
Used the cutting board block ( thanks....now to see if I can cancel my order from Brownells...) Tried heat gun.... wouldnt budge!! Put it in the chest freezer for 2 hours.... broke right loose!! no loctite on it ... You guys ROCK!!
Now wait for UPS to bring me my YH FF rail! |
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Should I use a barrel clamp on block or will a upper rec block work ok as well...?? Barrel vise block ONLY. The problems that come from using a receiver block of any kind include twisting or even breaking the upper receiver, particularly when your barrel nut isn't cooperating. Wow. This is completely backwards. Get a Peace River receiver block, use the internal support, you're not going to break the upper. Just discussed this earlier in the week http://www.ar15.com/forums/t_3_4/557269_Barrel_removal_.html&page=1 I respectfully disagree. With the barrel held in vise blocks, the pin has almost NO load until the barrel nut breaks loose, and then only the drag load from the nut riding over the upper's threads for perhaps 1/4 turn. When installing the barrel, there is minimal load on the barrel index pin because once the nut "catches," the barrel is essentially immobile and the torque is applying a draw force between the threads of the nut and the upper. On the other hand, even with a clamshell block the thin front section of the upper takes ALL of the torque load, which can be especially heavy when trying to loosen a stuck barrel nut. I tend to follow the TM's instructions unless there is a very strong reason not to. And I've used a Panther Claw to rebarrel an upper. Once. It was a royal pain, and I was constantly checking to see that the upper hadn't twisted while I was putting a LOT of force on the wrench to break the nut loose. That's where I learned first hand about the freezer trick (thanks QUIB!) and where I determined that this was a place to trust the manual. |
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You CAN damage your upper receiver. NEVER hold your upper receiver while tightening or loosening your barrel nut.
Get a good adjustable barrel clamp, not the one size fits all. Wrap your barrel in brown wrapping paper to keep the aluminum from marking your barrel. 55 dollars for the clamp. On a proper armorer's tool there is a 3/8 or 1/2 square. I would have to look at mine. That hole is there specifically to take the drive of a BREAKER bar for just such an occasion as your stubborn barrel nut. They do not need loctite. They not are supposed to HAVE loctite on them, only white lithium grease. If it does have loctite then it will be a bear to get off. Try the breaker bar or a pipe over the barrel nut tool with a second person holding the tool locked into the barrel nut. As a last resort Use a strong HEAT GUN. I suspect yours was not an industrial model. I have a wicked one from Grainer. Its HOT! This will not damage your upper or anything else if used properly. You are heating only to soften the loctite. But do be careful. Too much heat for too long can change the molecular structure of alum alloy and make it brittle. That is why a an alloy SCUBA tank that is in or near a fire must be condemned. It only takes about 30-60 seconds with a strong heat gun to loosen loctite. Try that WHILE someone is cranking on a really BIG breaker bar to loosen the nut. this part is critical. If you do the job alone, your work will have cooled by the time you get the wrench all in place. Still wont come off? Try it with a giant PIPE over your barrel wrench. a huge one! Do not over heat. If it doesnt come off with that method its welded on! Once removed. You WILL get this nut removed....clean off all the loctite and re assemble using only white l;ithium grease. Torque to specs. How? Use the same hole in your barrel nut tool! Line up your gas tube hole. |
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........my barrel nut wrench has 3/8" and 1/2". i believe the holes are for a torque wrench, not a breaker bar. you could use one in there though.
the heat gun won't hurt the aluminum too easily. even the industrial one––––as long as you don't put it on full blast and walk away for 1/2 hour 
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........my barrel nut wrench has 3/8" and 1/2". i believe the holes are for a torque wrench, not a breaker bar. you could use one in there though. the heat gun won't hurt the aluminum too easily. even the industrial one––––as long as you don't put it on full blast and walk away for 1/2 hour Most "stuck" barrel nuts aren't glued in place, they're just stuck. Heat up the NUT, not the upper and you'll do pretty much the same thing as sticking the upper in a freezer - make use of the different thermal expansion characteristics of steel and aluminum to loosen up the adhesion that naturally occurs when you have such tight connections. Some builders use Loctite between the BARREL and upper to "bed" it. Maybe that helps with accuracy, but it should not spill over enough to even touch the barrel nut. |
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