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Posted: 1/9/2006 11:15:27 AM EDT
I've got a DPMS barrel wrench, an upper vise block (encloses the entire upper and has a piece that goes where the BCG normally sits), a solid bench, and a vise mounted with big ol' bolts. However, I can't seem to keep from stripping the barrel nut when I'm tightening to get the "next" slot lined up so the gas tube goes into the receiver perfectly straight. I've tried both sides of the wrench and have stripped barrel nuts both ways.

How do you guys keep even tension on the wrench so it doesn't slip under load? Or am I torquing too much? I know the max torque value is 80 ft/lb - that's a lot of torque.

Thanks.
Link Posted: 1/9/2006 11:20:13 AM EDT
Use the side with all the teeth, not the side with 3 nubs. Press down directly on the wrench above the teeth with one hand, and turn the wrench with the other.
Link Posted: 1/9/2006 1:20:29 PM EDT
Be sure to use moly lube on the threads if you aren't already. Using a torque wrench attached to your barrel wrench, tighten the barrel nut to 30#, then remove the torque wrench. If the gas tube will clear a notch in the barrel nut, stop tightening there -- you are finished. If it will not clear, tighten until you get a notch, but do not exceed 80#. If it will not align a notch by 80#, tighten and loosen the barrel nut repeatedly. This will cause the overall torque value to drop and eventually you should be able to get it between 30-80#.
Link Posted: 1/9/2006 1:37:38 PM EDT

Originally Posted By vmpglenn:
I've got a DPMS barrel wrench, an upper vise block (encloses the entire upper and has a piece that goes where the BCG normally sits), a solid bench, and a vise mounted with big ol' bolts. However, I can't seem to keep from stripping the barrel nut when I'm tightening to get the "next" slot lined up so the gas tube goes into the receiver perfectly straight. I've tried both sides of the wrench and have stripped barrel nuts both ways.

How do you guys keep even tension on the wrench so it doesn't slip under load? Or am I torquing too much? I know the max torque value is 80 ft/lb - that's a lot of torque.

Thanks.



Great Question.

I have the same problem. Six builds and I stripped every one. I've been ultra careful to use the proper side of the wrench and keep even pressure on it. Every time I get close to the right spot it slips. I think the wrench I am using flexes under load. I bought it from Sherluk and it looks great but I can feel it open before it slips.

Not to hijack your post but who makes the best barrel wrench? I've used this one for the last time.
Link Posted: 1/9/2006 1:48:42 PM EDT
I have the book from Fulton Armory on building AR15s, and find it interesting that after going over all the torque values and how to measure them, they then say that virtualy no professional builder uses a torque wrench, a) because its so arkward to do so, and b) because you don't get fine enough control to accurately line up the gas tube hole.

I now just use the gas tube wrench, and make the nut tight, not worrying if its only 28 ft-lbs, and being pretty certain that I won't easily exceed 80 ft-lbs with just the wrench (at least not without being fully aware that I am making it very tight!).

Works for me ...

Actually, think about it - the barrel doesn't have to be held down ultra tight since when the bolt is locked, everything is locked up solid to the barrel -- the barrel only has to be solid enough to not flap around in the breeze.

The torque applied simply has to be sufficient to stop the barrel nut working loose over time.
Link Posted: 1/9/2006 1:54:23 PM EDT

Originally Posted By BigHitter:
Not to hijack your post but who makes the best barrel wrench? I've used this one for the last time.



Sully has tried about every barrel wrench known to man and swears that the Olympic Arms wrench is the best on the market. His opinion is good enough for me.

www.olyarms.com
Olympic Arms armorer's wrench -- #H28B -- $27
Link Posted: 1/9/2006 2:05:22 PM EDT
I rebarreled my Stoner. I replaced it with a post ban/no ban barrel.

When I removed the factory installed barrel, all it took was hand pressure on the barrel wrench. I have a GI type wrench, the rectangular kind with the place for the torque wrench to attach.

No extension, nothing... just hand pressure, and it did not take that much. The rifle never had any accuracy problems, and could not been more than snugged then turned to allow for the gas tube to align.

I only torqued my first build. The Stoner barrel change was right after that, and for all my other builds and barrel upgrades, I never torque the barrels.
Link Posted: 1/9/2006 2:39:43 PM EDT

Originally Posted By M4Madness:
Olympic Arms armorer's wrench -- #H28B -- $27 $22



Fixed it for you. Price must have dropped.


BTW, I use the DPMS wrench, and have never had a problem with it.

Link Posted: 1/9/2006 5:09:16 PM EDT
Another trick to tightening the barrel nut is to not attempt to line up the gas tube hole on the first shot. Tighten the barrel nut as far as you can then back it off. Do this twice more and on the final attempt you’ll usually find that it’s easier to reach alignment of the gas tube hole.
Link Posted: 1/9/2006 6:15:00 PM EDT
I do use moly grease on the threads - but I probably don't have enough on there. Loosening and tightening several times sounds like a plan - and I kind of thought that I was putting way too much torque on the nut, so I'll just get it tight enough so the barrel doesn't flap around.

Thanks all.
Link Posted: 1/9/2006 6:50:46 PM EDT
I'll order the Oly wrench today and be done with it.

Thanks for the input.
Link Posted: 1/9/2006 7:56:15 PM EDT
[Last Edit: 1/9/2006 7:57:01 PM EDT by Stickman]
I've been using the OA wrench for years. Anything else is a waste of time.


The side that is facing up in this picture is the side you want to use on the barrel teeth.

Link Posted: 1/9/2006 8:42:07 PM EDT
cool pic
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