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Posted: 4/5/2010 12:56:33 PM EDT
hello all, I am trying to put together my first upper and was wondering if I need a torque wrench to put the barrel nut on? Or will the multi wrench be enough? Do I just tighten the nut as tight as I can get it with my hands and then use the wrench to take it to the next gas tube hole? Will that be tight enough? Go easy on the newb. 
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A torque wrench is not necessary. Yes, you just tighten it up, back it off, re tighten, repeat about three times. On the final time snug it by hand then tighten to align it with the next gas tube notch. Try not to go past it though.
Torque is a wide range; 30 - 80 (I may be off a few lbs). The amount is of torque is determined by the last notch lining up. You can't really dictate the exact torque, but I usually find it's in the 40-50 ft lb range. I only use a torque wrench for the extra leverage and just because I'm curious to see where it stops. Don't forget the lube. (Edited for clarification) |
| i had to go to 144 ft lbs to get mine lined up right + I would advise to make sure the gas tube has the same degree of play left and right when you do line up the holes of the barrel nut and upper reciever because this will ensure your FF handguard will be true and level. I used a Larue |
| It's off the OP's question a little, but I used to align it by eye or use a gas tube - kinda trial and error. I bought a Schuster gas tube gauge from Midway (I needed to get the order over the minimum to avoid a charge) and it works great. It won't go into the nut's groove and through the receiver unless the nut is in perfect alignment. No more hit or miss or getting it together and finding the gas key rubs the tube on one side or the other. I think it was around $12. One of those lame tools you don't need, but if you have it it makes everything easier. |
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http://www.ar15.com/forums/topic.html?b=3&f=4&t=490149
I think lapping the receiver a little would result in less torque. If you ever need to take it off and get to that point again try taking a little off the face or squaring it up and it will probably get you algined at a lower torque. No guarantees, but it can't hurt. |
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