Never had this happen before. I was installing an LT 7" hand guard last night. I snugged up the barrel nut a few times and went to 30lbs torque. The gas tube hole was just past alignment so I had to go torque to the next hole. I did this in increments and when I got up to 85 lbs one of the pins sheared off of my DPMS multi tool. I am stuck without another wrench. I had lube on the barrel threads and inside the barrel nut. Could I have done anything different? I bought the tool from Midway and will see if they will replace it. Any recommendations on a different wrench or completion of this project? thanks guys
Barrel Nut - 30 Ft. lbs. Minimum, not to exceed 80 Ft. Lbs. to align the next slot in the barrel nut.
I don’t see how you’d need an extra 50ft/lb’s to reach the next slot. Any chance your torque wrench is out of calibration?
My torque wrench is okay. When I get the replacement multi tool I will disassemble, inspect and retry. Midway is replacing the DPMS with a Stoner at no cost. They are out of the DPMS and did not know when they would be getting them in. In the past this has not been a problem but I have never done a LT handguard before. I did not want to loosen from 30lbs to align the holes. When the tool broke it left the alignment half way between two holes.
It’s not uncommon for that to happen with standard barrels nuts and the barrel nuts with some free float tubes. Usually trying a couple of different barrel nuts fixes the problem.
Yep, happens all the time (have several broken DPMS wrenches).
One other thing, 80ft LBS is about the MAX you should go an would try to stay more around the 60+ mark.
C4
Okay so is my next move to ask Mark at LT for a different barrel nut?
So you cannot get the 3:44:21 PM barrel nut on between 30-80ft lbs?
C4
At this point with the broken wrench I can’t go forward or take it off and retry. I am second guessing the hell out of myself that I did not go too far and am trying to torque up to the second hole in rotation. I really don’t think so but it could be possible. A helpless feeling not being able to get it fixed right away. I don’t like having broken stuff.
An additional note. I have changed out 12 carry handle uppers for flat top uppers without any issues.
Funny that you should mention this. I broke a DPMS wrench two weeks ago doing the same thing.
Ken Elmore (Specialized Armament) has stated that LT rails require a tremendous amount of torque - I have seen the wrench that he uses, and it’s BIG.
I have sheared a pin on two different DPMS armorer wrenches installing LaRue rails.
Knew another guy that sheared a pin off a DPMS armorer wrench installing a rail.
I purchased this armorers wrench and haven’t had any problems:
http://www.bravocompanyusa.com/YHM-Forearm-Wrench-p/yhm-9621%20ff%20wrench.htm
S/F,
Jeff
How much did you have to torque the nut to get the holes to line up? Thanks for all of the replies.
When installing anything with an aluminum barrel nut like YHM, PRI, LaRue etc you should use a barrel nut wrench that has 3 or more LONG pins like the YHM wrench or PRI wrench. The long pins are twice as long if not longer than the pins used on DPMS/USGI type wrenches. If using a short pin barrel nut wrench on barrels nuts it’s not if it’s when will you break the wrench or FUBAR the barrel nut. Proper tools for the job = damage free
PRI wrench
YHM wrench
I’ve torqued some barrel nuts beyond 80ft lbs on occasion using the 5 pin PRI wrench and have never broken the wrench nor damaged the barrel nut. Most of the time as long as it’ll align in under 100ft lbs I’ll go with it. If it’ll take more than that I’ll lap the front of the receiver and/or try another barrel nut. This is the biggest reason why I prefer Daniel Defense Lite Rails and RIS II rails over everything else. Daniel Defense has taken ‘barrel nut gas tube alignment’ out of the equation! I simply torque their barrel nuts to 70ft lbs and it’s done.
the PRI wrench is nice
its HEAVY for its size. i don’t see it shearing anything, with the mass of that thing and all of its teeth.
Been there done that.
I drilled out the broken area on the wrench and installed 3/16" SS pins.
I had the pins on hand since I’ve broken the pins on the YHM wrench too. Those are easy to replace.
how about a shim?
I’ve used them many times. Most people don’t know they exist.