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9/23/2010 5:39:00 PM EDT
I have a cmmg 6.8 upper and I think they put red loctight on the barrel nut.  What tips do you have for getting it off.
9/23/2010 6:01:03 PM EDT
[#1]
First off, you need a rock solid vise to hold the upper or the barrel.  I'd go with a barrel vise jaw solution for this because of the amount of torque you're going to have to apply.  It's also a good idea to have a barrel wrench like the DPMS Multi Tool, because you want to grab as much of the barrel nut as possible.  Use a breaker bar, not a torque wrench.

Put the upper in the freezer for about 45 minutes.  Timing is important here-too long or too short and it won't work.  The steel will contract more slowly than the aluminum, so that should loosen up the nut a tiny bit.  Now put it in your vise and apply the wrench and breaker bar.  Put a LOT of effort into the bar-it works best if you're applying downward force on the bar because you can add your body weight to it.  If necessary, get a cheater and put that on the breaker bar to increase the leverage.  Make sure the wrench stays on the nut and just PUSH DOWN.  Get friends to add their weight if needed.  Seriously.

The funny thing about tight barrel nuts is that most times, there's nothing between the nut and the upper but a little grease.  And after it's been shot a few times, that "30-80 ft/lbs" of torque applied to install the barrel nut has become irrelevant-the nut gets stuck.

Good luck, and let us know how it comes out.
9/23/2010 6:24:33 PM EDT
[#2]
Heat the nut up with a torch to break the loctite bond....
9/23/2010 7:43:59 PM EDT
[#3]
where can I get the upper vice block I have the dpms claw but I guess I need the clam shell style.
9/23/2010 8:06:37 PM EDT
[#4]
http://www.brownells.com/.aspx/pid=22385/Product/AR_15_M16_UPPER_RECEIVER_ACTION_BLOCK
9/23/2010 8:06:46 PM EDT
[#5]
Brownell's, among other places.
9/23/2010 11:04:47 PM EDT
[#6]
Heating will help melt the Loctite, but otherwise freezing is definitely the way to go. I just was taking a barrel out recently (this week actually) and had problems with the barrel nut. Thirty minutes in the freezer and it came right off.
9/24/2010 6:04:20 AM EDT
[#7]
will this work
http://www.midwayusa.com/viewProduct/?productnumber=829522
9/24/2010 6:28:06 AM EDT
[#8]
Quoted:
will this work
http://www.midwayusa.com/viewProduct/?productnumber=829522


Yes.  A clamshell upper fixture is more likely to protect the upper than an insert-type like the Panther Claw from DPMS.
9/24/2010 6:52:24 AM EDT
[#9]
Thanks for the help the tools are ordered and will be here tuesday.  Pictures will be up as soon as its done.
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