Barrel torque magpul wrench

[MistWolf]

"Special Tool" or "Specialty Tool" is how the military defines any tool the equipment maker requires for a specific job, like torquing barrel nuts on an AR. The MagPul wrench is a special tool. Turning the MagPul wrench 90 degrees without compensating for shortening the length will result in a reduction of applied torque

[elephantrider]

errr, am I missing something, but aren't we arguing about 30 ft-lbs +/- some value that depends on the length/offset of the wrench?
The actual value that the nut is being torqued to can be calculated. Since the spec is a min. of 30 ft-lbs, would this also not really be an issue unless you run into one of those receiver, barrel, nut combinations that wants to time around that 30 value, AND you are concerned about hitting the min?

[Iraqgunz]

I am well aware of what the manual says, and what wrenches are used. In addition to the over 2,000 AR's that I have worked on or built over the last few decades.

The Colt drawing says 30 ft-lbs, not to exceed 80 ft-lbs. No mention of tools or anything else. This would indicate that the nut is to be torqued to 30 to 80 ft-lbs, however you choose to get there.

And, while the manual shows the wrench in-line it also states "Torque is measured when both wrenches are used together," indicating that the length of the wrench must be accounted for when torquing the nut.

[Iraqgunz]

https://www.youtube.com/watch?v=LRP8d7hhpoQ

Not to mention they went to the trouble to draw the forward assist, charging handle, vice and it's mechanism.... One would expect they drew the two wrenches in that manner for a reason.

As well, "measured together" very well means.... place the two tools "together" as the picture indicates then tighten and "measure" the torque as any more complicated arrangements will make no difference in context.Thus "Torque is measured when both wrenches are used together," ...

Reading anything else into it or trying to apply torque wrench science to it, it simply not necessary and only serves to complicate what is a basic non critical task like putting your pants on.

[Iraqgunz]

The torque value varies because the alignment of the barrel nut must be achieved with 30 ft./lbs. being the min. It also takes into account the tolerances in threads with barrel nuts and upper receivers. This is why other nuts like the Geissele, BCM KMR, Centurion Arms CMR, et al.. all have a set value. Because there is no alignment to be achieved.

errr, am I missing something, but aren't we arguing about 30 ft-lbs +/- some value that depends on the length/offset of the wrench?
The actual value that the nut is being torqued to can be calculated. Since the spec is a min. of 30 ft-lbs, would this also not really be an issue unless you run into one of those receiver, barrel, nut combinations that wants to time around that 30 value, AND you are concerned about hitting the min?

[elephantrider]

The torque value varies because the alignment of the barrel nut must be achieved with 30 ft./lbs. being the min. It also takes into account the tolerances in threads with barrel nuts and upper receivers. This is why other nuts like the Geissele, BCM KMR, Centurion Arms CMR, et al.. all have a set value. Because there is no alignment to be achieved.

Right, I think we're essentially saying the same thing. Non-timed/proprietary barrel nuts call out a torque value to set, tighten, click, and done. Usually 40-50lbs depending on the mfg. The exact torque can be achieved by turning the nut adapter 90 degrees, or reducing the torque setting the correct amount to account for the addition to the lever arm length from the nut adapter if it is used in-line with the wrench (<simple ratio calculation). Even if the wrench/nut adapter is used in-line and the additional lever arm length is not accounted for, then you are probably still good as you should not add too much torque unless the wrench is relatively short, and/or of the adapter has a relatively large offset.

Same logic applied to the specification that was linked, with the torque tool used inline with the wrench/adapter offset,. the 'minimum' is actually more than 30ft/lbs? With the torque tool held inline, per the spec, it appears the spec is actually using more than an absolute min value of 30ft/lbs, no? The timing of the nut teeth also needs to be taken into account of course.

[GrumpyM4]

And with the known torque values that the threads can take, the torque values given by those aftermarket manufacturers are pretty much pulled out of thin air and are just as malleable as the USGI version of assembly.

We know that the barrel nut, barring extraordinary circumstances, won't come off at 30ftlbs, and therefore the aftermarket values are pretty much the minimum plus a little extra to account for the "just in case".

All of that being said, with that kind of variance, who gives a flying **** if the tool is at a 90 degree angle to the torque wrench. Do it like the manual says because that is a known, set standard, that is pretty much guaranteed to work, 9999 out of 10000 times.

Anything else is retarded as ****, full on mental masturbation, and overthinking one of the most simple parts of assembling a goddamn AR. The fact that there are this many replies in a thread about so simple a process is, well, pretty ****ing dumbfounding.

[MWL]

People shouldn't get too caught up in what the military manuals state.

For a long time, the military manuals stated that the "castle nut" needed to be torqued to 40 inch pounds plus or minus 2 inch pounds.

I know of at least one major player that was assembling their AR15s to that standard until I pointed it out to them during an armourer course three years ago. The department manager ended up calling the AMU to confirm that the latest manual had been corrected.

Regards.

Mark

[hdrolling]

Well if nothing else I've found this thread informative, Just saying.......

[MegademiC]

Alright thanks guys, I'm confident (100%), that it's within the spec.

Related question, how far from the center of the barrel is the torque wrench head on a milspec wrench? Just looking to compare to the magpul wrench.