Wrapping up - Tightening Barrel Nut to Upper Receiver... Special tools needed to avoid twisting ?

[Lfryklu]

Hi Guys,

With help from a number of you last year, I'm wrapping up, or at least I think I'm wrapping up my .308 build, but still the handguard I want is BO by Aero Precision & has been for about a year now.

Lots of 15" HG's are available from AP, but I want a 12" (12.7") by their measure anyway an M-Loc version, to put on my 18" Criterion barrel.

So, in meantime while waiting thought I'd move forward and mount the barrel to the AP Upper Receiver w/Aero Barrel Nut, then mount a HG later.

But, I'm reading though different web articles that while torqueing the nut, its possible to twist the Upper Receiver out of shape.

On an AR-15 .300 BO build that I did last year, I just put the upper & lower into a vise block set, inserted the barrel into the upper put my Armorer wrench tool on the nut, connected my torque wrench and then hit the spec. Then I adjusted the gas block, put the handguard on & it was done.

This build though is LR-308 so its similar, but is still a little different.

Being physically a larger upper & lower, don't think will fit my AR block set, which right now I cant find anyway, but now I'm thinking I may need different approach.

I contacted Brownell's Tech Support and they recommended a 'Barrel Extension' wrench - 080-001-040WB
308AR Barrel Extension Torque Tool   Mfr Part: 100571

Is this what I need to keep from accidentally twisting the upper when torqueing the barrel nut down to spec? Supposedly to more evenly distribute the torque to avoid twisting the upper.

I chatted with Aero Precision & told me they use something similar - https://www.midwestindustriesinc.com/MI-Upper-Receiver-Rod-308-p/mi-308urr.htm

Is there a simpler way to get this done, with just my Armorer's wrench, and torque wrench?

Possibly just a larger vise block set to accommodate the larger .308 upper & lower ?

Let me know.

Thanks & best regards,

Lfryklu

[Czgunner]

I've put together many, many small frame uppers and the only time I've had an issue is when I pulled apart my dad's DPMS upper to change the handguard. I have the Brownell's tool, but the barrel would twist while tightening the barrel nut and cause enough misalignment that the BCG wouldn't go into battery. I got it lined up after a few tries. Not sure why, the pin looked a little buggered, but not too bad (DPMS OEM upper) and the pin slot looked fine too. There was just enough tolerance stacking that the barrel would twist. That M.I. wrench is better, but not sure it would solve my issue. I have the M.I. small frame tool and it does seem to hold things tighter.

[DustBuster]

I put my barrel into a vise wrapped in Thick Leather.  I’ve done this twice now.  I have a fluted Barrel and was a tad concerned over stress concentrations directly on the flutes, but I only cranked the Vice just tight enough.  As I reached about 50 ft-lbs Everthing started to slip but I got it done.  My barrel tong needed to be set hard against the receiver slot side for best feed ramp lineup, so the slop in that slot was no concern.. Same exact procedure as using a reaction rod.  Vice closer to barrel extension when doing barrel nut and closer to gas port when doing muzzle brake, to eliminate more internal torsional distance on the barrel itself.  I think if you had a solid non-fluted barrel you could crush the living snot out of the barrel and it wouldn’t  hurt anything.

If I had a reaction rod I would use that.. When I crank on my Vice really tight, I hear some weird sounds, but I’m pretty sure it’s just my Vice whining and not the barrel cracking.  An engineer would do a calculation using Poissons Ratio.  I don’t think I reached yield stress of the steel though.  The slop in the slot of the receiver got me slightly misaligned the first barrel I did with this method but on this second time, it didn’t matter, I got lucky.  So in a nutshell, I think my upper did not suffer any twisting forces on it.

Edited January 27, 2022 by DustBuster

[jtallen83]

10 hours ago, Lfryklu said:

Possibly just a larger vise block set to accommodate the larger .308 upper & lower

Used those for uppers on many builds without issue. I did end up with a Geissele reaction rod for small frame but that was due to trying to fix someone else's use of an insane torque level to swap the handguard. I've never needed to use any where near enough force to twist a receiver in the block, I continue to use a barrel clamp as close to the muzzle device as possible for that work because it just feels wrong to apply the clamping force so far from the the work on a slender tube with the leverage factors involved. Odds are I will get a rod for the large frame as well, mostly because of the versatility it has holding the upper solid in different positions and the easy on off for all sorts of work.

[Lfryklu]

Hey Guys,

I really appreciate the feedback and input of sharing with me the mounting methods you each used.

Have not decided on buying a special tool yet, or not.

I'm retired, & no job, so budget is pretty tight, but I don't want to trash my rifle trying to finish it up.

Got my thinking cap on, and trying to figure out next move.

Almost leaning toward the Midwest Industries tool, as this is what Aero told me they use for this task.

Looks similar to the Brownell's tool, but looks like there is additional reinforcement on top provided to the BCG channel area.

Am I missing something?

Hmmmmmm.....

Thanks again.

Best regards

Lfryklu

[Czgunner]

1 minute ago, Lfryklu said:

Hey Guys,

I really appreciate the feedback and input of sharing with me the mounting methods you each used.

Have not decided on buying a special tool yet, or not.

I'm retired, & no job, so budget is pretty tight, but I don't want to trash my rifle trying to finish it up.

Got my thinking cap on, and trying to figure out next move.

Almost leaning toward the Midwest Industries tool, as this is what Aero told me they use for this task.

Looks similar to the Brownell's tool, but looks like there is additional reinforcement on top provided to the BCG channel area.

Am I missing something?

Hmmmmmm.....

Thanks again.

Best regards

Lfryklu

Yeah, that "additional reinforcement" sits inside the BCG gas key channel and helps to keep the upper from rotating while tightening or loosening the barrel nut. If there is a lot of slop in your upper, you can add some paper or tape to the tool to shim the channel and prevent movement. They work awesome. Highly recommend.

[Lfryklu]

Hi,

I chatted again with Aero Precision & told me they have no issues with the Midwest Industries tool - https://www.midwestindustriesinc.com/MI-Upper-Receiver-Rod-308-p/mi-308urr.htm

? - Does any one have one that they would be willing to either rent, or sell ?

Think I'm leaning this way right now.

Anyone willing ?

LMK

Best regards,

Lfryklu

[Lfryklu]

Guys,

Well, finally Aero Precision made up some 12.7" Gen2 MLOC FDE handguards to sell, that is the final component I have been waiting for to complete my .308 project build.

Now that the handguard has been purchased, and on its way to me I am back to my previous question.

A gun guy, not sure if he is a 'Smithie', or not told me that the tool they use at their shop for both M4 and M5 upper receiver retention in a vise works just fine to hold the upper receivers in place to crank/torque the barrel nut down.

When I told him that Aero recommends a 65 Ft. Lb. torque setting, he 'was surprised', as he told me that most upper mfg.'s advise only a 35-40 Ft. Lb. torque setting.

So my question to the .308 group is - Is he right that the M4 upper retention tool that goes in a vise also will work for M5 uppers?

Or, is a 65 Ft. Lb. torque setting just 'too much' for the possibility of twisting my Aero upper receiver using the M4 tool?

When I spoke with Aero about it, they told me about the Midwest Industries is the tool (link - https://www.midwestindustriesinc.com/MI-Upper-Receiver-Rod-308-p/mi-308urr.htm ) that they use at Aero for barrel nut torqueing of M5 uppers & barrels  at their factory.

? - Is the M4 tool that the local gun shop here uses for all the barrel nut torqueing of uppers & barrels  at their shop going to do the job for me on my Aero upper, barrel nut, & Criterion barrel project, or not?

Bummer to have to buy the $150 tool for my 'one-time' use of it for my project, but I don't want a twisted upper at the end of my project, now that I've waited over a year for Aero to finally make 12.7" handguards again.

Just asking what you guys think, or maybe someone has one that I could rent, for my  'one-time' use of it?

I'm at the point of having to go one way, or the other.

Let me know what you all think.

As always, really appreciate the knowledge share the guys in the forum provide.

Best regards.

Lfryklu

[98Z5V]

3 minutes ago, Lfryklu said:

A gun guy, not sure if he is a 'Smithie', or not told me that the tool they use at their shop for both M4 and M5 upper receiver retention in a vise works just fine to hold the upper receivers in place to crank/torque the barrel nut down.

When I told him that Aero recommends a 65 Ft. Lb. torque setting, he 'was surprised', as he told me that most upper mfg.'s advise only a 35-40 Ft. Lb. torque setting.

So my question to the .308 group is - Is he right that the M4 upper retention tool that goes in a vise also will work for M5 uppers?

Depends on what he's talking about - you didn't state it, and we don't know.  Contact him for clarification on exactly what he's using.

M16 barrel nut torque spec is the same as M4, and that's 35~80 ft/lb, per the TM on both weapons.  .308ARs will b the same - unless the handguard manufacturer states something different (it;s their handguard, and their barrel nut).  Aero says 65, then it's 65 for Aero's handguard and barrel nut.  That the guy was surprised shocks me - he should already know that standard barrels nuts sometimes have to go to 80. 

Ask him specifically how he's securing the upper, to tighten the barrel nut.  From what I read, I interpreted that he's clamping the receiver itself into a vise.  That can work for tightening, because of the rotation - but if you try to take one off like that, you can crack the upper receiver at the front bottom of the ejection port.  If that's his practice, it's bad practice. 

Ive been using Geissele Reacfion Rods for a long time, both small-frame and large-frame, and have never had an issue with using them.  They work well.

[jim3326]

47 minutes ago, 98Z5V said:

Depends on what he's talking about - you didn't state it, and we don't know.  Contact him for clarification on exactly what he's using.

M16 barrel nut torque spec is the same as M4, and that's 35~80 ft/lb, per the TM on both weapons.  .308ARs will b the same - unless the handguard manufacturer states something different (it;s their handguard, and their barrel nut).  Aero says 65, then it's 65 for Aero's handguard and barrel nut.  That the guy was surprised shocks me - he should already know that standard barrels nuts sometimes have to go to 80. 

Ask him specifically how he's securing the upper, to tighten the barrel nut.  From what I read, I interpreted that he's clamping the receiver itself into a vise.  That can work for tightening, because of the rotation - but if you try to take one off like that, you can crack the upper receiver at the front bottom of the ejection port.  If that's his practice, it's bad practice. 

Ive been using Geissele Reacfion Rods for a long time, both small-frame and large-frame, and have never had an issue with using them.  They work well.

I read it as he's using the top rail to clamp in a vise with the Wheeler (or similar) jig. That's what I have used in the past. Slide it onto the rail and clamp. Also helps to align the hand guard by sliding it over both rails. There is a lot of meat to clamp on to so I saw no issue. Should I re-think this method?

Edited August 17, 2022 by jim3326

[98Z5V]

57 minutes ago, jim3326 said:

I read it as he's using the top rail to clamp in a vise with the Wheeler (or similar) jig. That's what I have used in the past. Slide it onto the rail and clamp. Also helps to align the hand guard by sliding it over both rails. There is a lot of meat to clamp on to so I saw no issue. Should I re-think this method?

That tool works both ways.  Clamp the pic rail, or use the pin-points on the upper.  I'd run that with the pic rail, but I don't like using the pin-points for tightening a barrel nut.  Here's what it does, both ways:

This is a DPMS LR-308 upper mounted via the pic-rail:

This is mounting through the pin-points - I wouldn't do this, myself.

[jim3326]

8 minutes ago, 98Z5V said:

That tool works both ways.  Clamp the pic rail, or use the pin-points on the upper.  I'd run that with the pic rail, but I don't like using the pin-points for tightening a barrel nut.  Here's what it does, both ways:

This is a DPMS LR-308 upper mounted via the pic-rail:

This is mounting through the pin-points - I wouldn't do this, myself.

The first pic is how I use it.

[98Z5V]

3 minutes ago, jim3326 said:

The first pic is how I use it.

Shouldn't ever present a problem. On or off.  

[Lfryklu]

Thanks for the replies guys.

I called to see exactly what the guy at the Gun Shop was using, but not able to connect yet to see exactly what brand tool it is.

Looking over your suggestions and recommended tools, what the shop was using appeared to be a 'Reaction Rod'

Square end tightens on the vise and the Upper goes through the bolt channel inside if the upper receiver to engage with the barrel?

Been quite sometime since I've looked at it.

And now can see different tools, and methods can be used.

The Midwest Industries tool has a long square piece integrated right on the Reaction Rod that matches the inner dimensions of the charging handle well inside the upper - see link - https://www.midwestindustriesinc.com/MI-Upper-Receiver-Rod-308-p/mi-308urr.htm 

That's the added piece that the Aero folks were telling me kept the upper receiver form twisting as torque was applied, that makes it different than a standard reaction rod.

I've not seen the Wheeler Delta Series tool, and that's not what the shop was using, outside of the upper receiver on a vise, in either position in pix sent.

So, now that I think I have the jargon down better, they must be using a multi-purpose reaction rod type tool for both M4 & M5 upper receivers.

I can see looking at the Midwest Industries tool that the added piece, about 4" long that rides through the charging handle channel, would provide extra stability to the upper receiver, as torque on the barrel nut is applied,

I think my question is - will a standard 'reaction rod' tool work ok on an M5 upper when applying 65 Ft. Lbs. of torque?

Or, do I need to buy the Midwest Industries tool, to ensure no twisting of the upper?

Does that explain better what I'm trying to say?

The guy at the shop said they use their standard tool for both M4 & M5 uppers, but again it was his surprise at the 65 Ft. Lb. torque setting number that caused my concern.

Maybe they have only worked on lower torque requirement uppers?

Check out the Midwest Industries link above and if you think its 'overkill' for what I need to do on my Aero upper at 65 Ft. Lbs. torque.

Thanks so much your responses.

Best regards.

Lfryklu

[98Z5V]

11 hours ago, Lfryklu said:

Looking over your suggestions and recommended tools, what the shop was using appeared to be a 'Reaction Rod'

Square end tightens on the vise and the Upper goes through the bolt channel inside if the upper receiver to engage with the barrel?

Been quite sometime since I've looked at it.

No worries - it'll work.

11 hours ago, Lfryklu said:

That's the added piece that the Aero folks were telling me kept the upper receiver form twisting as torque was applied, that makes it different than a standard reaction rod.

That's a non-issue.  Something invented for a problem that doesn't exist.  That little MI piece on top is completely unnecessary.  If your upper twists when trying to put on a barrel nut, whist using a reaction rod - then the barrel extension wasn't properly torqued to 175lb/ft to the barrel in the first place.  Better you find that out when trying to install a handguard or barrel nut, than later.  If that MI little block on top becomes useful, then your entire barrel wasn't put together correctly from the barrel-maker. 

11 hours ago, Lfryklu said:

So, now that I think I have the jargon down better, they must be using a multi-purpose reaction rod type tool for both M4 & M5 upper receivers.

I've never seen such a device, works on both.  Only ones I've ever seen thus far are either small-frame ARs or large-frame ARs.  Maybe something new came out, and I didn't notice. 

[Lfryklu]

Hi,

Really appreciate your reply, and feedback.

The Midwest Industries tool is what the folks at Aero Precision use to complete their upper receiver assemblies.

But, it sounds like I'm 'good to go' at 65 Ft. Lbs. torque with a standard reaction rod, that works with either M4, or M5 upper receivers.

Mine is an M5, LR308 Platform

Is that correct?

Thanks

Lfryklu

[jtallen83]

2 hours ago, Lfryklu said:

65 Ft. Lbs. torque

That's good and stout, if I can get the gas tube to pass at 35- 40 ftlbs I'm happy unless I would happen to have a special part that told me different, I start getting nervous when I see 55 ftlbs.

[Lfryklu]

Thanks for your comment.

Yeah, 65 Ft. Lbs. seems to be a really high torque spec.

I guess that is why Aero uses, and recommends the Midwest Industries tool with the charging handle inner brace on their reaction rod tool for torqueing the barrel nut to the upper.

So, you think it's ok to use a lower torque number for this job?

I just want to get it on, and get to the range.

I really do appreciate candid feedback about using a lower torque value, and still be fine.

So, let me ask now - What lower torque value would be acceptable to get the job done.

Any other comments ?

Lfryklu

[98Z5V]

7 hours ago, Lfryklu said:

So, let me ask now - What lower torque value would be acceptable to get the job done.

Already been stated,. above in this thread.  It was this , below vvv...

On 8/16/2022 at 8:03 PM, 98Z5V said:

M16 barrel nut torque spec is the same as M4, and that's 35~80 ft/lb, per the TM on both weapons.  .308ARs will b the same - unless the handguard manufacturer states something different (it;s their handguard, and their barrel nut). 

 

[Lfryklu]

Thanks Guys,

Will let you all know how it does at the range.

Handguard still not delivered, but should be here soon.

Appreciate all the assistance,

Best regards.

Lfryklu

[Lfryklu]

Thanks for all your feedback guys !

I went to Atomic Tactical, in Savage MN, to wrap up and had some really great assistance from Kenny & Ron with final assembly using a standard reaction rod to mount the handguard to 55 Ft. Lbs.

Told me that would be just fine, and then wrapped up putting on the Aero 12.7" Handguard I have been waiting for delivery over 1 year.

Finally wrapped up the rifle with installing the Precision Arms muzzle break I selected.

All parts function correctly, and now its time for a scope.

Think I've decided on a Vortex Strike Eagle 4-24x50 with EBR-4 MOA SE-1627.

I like a grid scope myself personally, and seems this is best for my budget, using an Aero Precision 30mm scope mount in FDE finish.

The scope is black, and I like the black & FDE contrast parts, as shown in the pix below.

Aero Precision upper & lower, Criterion 18" barrel, Aero handguard, Precision Arms muzzle break, Rise trigger w/anti-walk pins, Magpul soft handgrip and stock.

Well, just a little excited to get a scope on it and get to the range.

Again, appreciate all the feedback.

Best regards,

Lfryklu

[Steve crawford]

looks good to me

[unforgiven]

Very nice brother 🍻🍻

[Jarhead504]

Nice looking rifle.  Looks purposeful.

Jarhead