View Full Version : Best way to hold upper while TQ barrel nut?
I have a Gen I Geissele reaction rod but have found out through talking with more experience people that they can/will shear the barrel extension pin.
SomeOtherGuy
01-04-16, 10:02
I have a Gen I Geissele reaction rod but have found out through talking with more experience people that they can/will shear the barrel extension pin.
I would be VERY interested to hear who those "more experience people" are. The major purpose of the reaction rod is to allow you to tighten barrel nuts (and muzzle devices) easily and without putting stress on the receiver, which is a weaker part than the barrel extension. If the barrel is properly assembled, with the barrel extension properly torqued on the barrel itself, there is over 100 ft-lbs of torque on that joint. You shouldn't be torquing a barrel nut past 80 ft-lbs at most. So if things are correct, there should never be stress on the barrel extension pin, which isn't meant to be a load bearing part anyway, just a locating point.
I've used a reaction rod for several barrel nuts and 15+ muzzle devices with zero issues. It's my preferred way of doing things, although I have also done barrel nuts using receiver blocks.
I would be VERY interested to hear who those "more experience people" are. The major purpose of the reaction rod is to allow you to tighten barrel nuts (and muzzle devices) easily and without putting stress on the receiver, which is a weaker part than the barrel extension. If the barrel is properly assembled, with the barrel extension properly torqued on the barrel itself, there is over 100 ft-lbs of torque on that joint. You shouldn't be torquing a barrel nut past 80 ft-lbs at most. So if things are correct, there should never be stress on the barrel extension pin, which isn't meant to be a load bearing part anyway, just a locating point.
I've used a reaction rod for several barrel nuts and 15+ muzzle devices with zero issues. It's my preferred way of doing things, although I have also done barrel nuts using receiver blocks.
Don't shoot the messenger! lol Both commented on why the genII was the release to help put force on the ejection port. However I am with you, I do not like putting stress in to the receiver. Often I use handguards that do not need to be index (BCM KMR for example).
Get ready for the Reaction Rod love fest.
I think I'm the only one here that doesn't like it. I would much prefer something like the (not actually available yet) Windham Weaponry barreling jig. I did buy the Geissele Super Reaction Rod hoping that it would solve the index pin shearing problems that you get with the original Reaction Rod but the brass wedge system is a fiddly pain in the ass to use when installing a barrel.
Wayne Dobbs
01-04-16, 10:41
If the barrel is properly assembled, with the barrel extension properly torqued on the barrel itself, there is over 100 ft-lbs of torque on that joint...
The barrel extension is torqued on at the factory (Colt) with 150 ft-lbs of torque.
What about the Magpul BEV block?
I'm trying visualize how the use of a reaction could put that kind of stress on a steel pin embedded in a steel barrel extension. It seems all the tightening stress would be at the receiver/barrel nut interface. At most the receiver would try and turn as the barrel nut is tightened....and widened the slot where the pin fits in the receiver..not shear the pin off. I haven't use a RR, so I'm not sure that the receiver would even turn upon barrel nut tightening.
What about the Magpul BEV block?
This is what I use.
I'm trying visualize how the use of a reaction could put that kind of stress on a steel pin embedded in a steel barrel extension. It seems all the tightening stress would be at the receiver/barrel nut interface. At most the receiver would try and turn as the barrel nut is tightened....and widened the slot where the pin fits in the receiver..not shear the pin off. I haven't use a RR, so I'm not sure that the receiver would even turn upon barrel nut tightening.
The way it was explain to me is that when tightening the barrel nut there is nothing to hold the receiver from twisting. There's be many reports now that I'm looking for them regarding shear pins and the Reaction Rod.
Has anybody actually seen this happen with their own eyes, or is this theoretical hogwash?
Auto-X Fil
01-04-16, 12:05
I have always clamped the receiver in a bench vice. I use a block of wood on either side, and obviously clamp the flat lower surface and the picatinny rail top, with the upper on its side. I have never had an issue with this, although I've never had anything horribly seized, either.
The downside is that you can't have an optic mounted, so if you have a scope that's a pain to remove, and want to swap muzzle devices, this wouldn't work so well.
I hold the upper (in a "clamshell" type of holder) when tightening barrel nuts.
I hold the barrel (with a Reaction Rod type of holder) when tightening muzzle devices.
Joe Mamma
Has anybody actually seen this happen with their own eyes, or is this theoretical hogwash?
If it were theoretical hogwash there wouldn't be so many pictures to prove it.
If it were theoretical hogwash there wouldn't be so many pictures to prove it.
So, you've seen it happen?
Somebody made an interesting observation; the magic word was "seized". It makes sense that a properly torqued barrel would possibly require higher torque to loosen, however wouldn't it occur to apply heat before brute force, considering the different expansion rates of the metals involved? It seems like the majority of those failures might have been easily prevented...
Auto-X Fil
01-04-16, 13:44
I agree with that. Years of wrenching on motorcycles and cars and bicycles have given me a decent feel for "enough force" for a given fastener size. If it doesn't come off with what feels like a reasonable pull, it's time for heat, and maybe penetrating oil.
So, you've seen it happen?
Somebody made an interesting observation; the magic word was "seized". It makes sense that a properly torqued barrel would possibly require higher torque to loosen, however wouldn't it occur to apply heat before brute force, considering the different expansion rates of the metals involved? It seems like the majority of those failures might have been easily prevented...
There was a picture here not two weeks ago of a sheared pin. Also I believe Iraqgunz said he had 1(one) shear upon dis-assembly of a highly over torqued nut.
It's pretty well known that it can happen.
I'm having a hard time visualizing how a clamped receiver would prevent the pin from shearing with a seized barrel nut compared to a reaction rod. Either way the force is going through the pin.
So, you've seen it happen?
Somebody made an interesting observation; the magic word was "seized". It makes sense that a properly torqued barrel would possibly require higher torque to loosen, however wouldn't it occur to apply heat before brute force, considering the different expansion rates of the metals involved? It seems like the majority of those failures might have been easily prevented...
I have not seen it happen in person but I have seen it posted about more than enough times to believe it really happens. It does happen mostly with stuck barrel nuts but it has on occasion happened on assembly as well.
Let's assume seized means that the threads of the receiver are fused to the threads of the barrel nut such that any applied torque to the nut creates a tendency for the entire receiver to rotate. With an unsupported receiver that rotation is largely opposed only by the indexing pin (some opposition is created by friction between the receiver face and barrel extension shoulder). With a supported receiver most of the rotational opposition is taken by the supporting fixture. With a supported receiver the only force directed through the pin is the result of the rotational tendency created by friction between the barrel nut and the barrel extension shoulder.
I'm having a hard time visualizing how a clamped receiver would prevent the pin from shearing with a seized barrel nut compared to a reaction rod. Either way the force is going through the pin.
Also, no one should assume that the aluminum part in an system of mating parts will automatically be the part to fail simply because it is the weaker material (7075 T6 actually has a higher tensile strength than many low alloy, low carbon steels in the annealed condition). You need to look at actual stress developed in each part.
I'm having a hard time visualizing how a clamped receiver would prevent the pin from shearing with a seized barrel nut compared to a reaction rod. Either way the force is going through the pin.
What Eric D. said, it's pretty simple to understand really... The threads on the barrel nut are usually seized to the threads on the upper, the inside clamp face of the barrel nut and the upper receiver extension flange clamp face don't usually become seized to the barrel extension flange.
This is why/how you can shear an index pin by using upper receiver vise blocks to remove/install a muzzle devise even though the barrel nut was properly torqued to spec. The friction clamping the flange is less than the friction between the threads of the barrel nut and upper receiver.
rcoodyar15
01-04-16, 17:33
What Eric D. said, it's pretty simple to understand really... The threads on the barrel nut are usually seized to the threads on the upper, the inside clamp face of the barrel nut and the upper receiver extension flange clamp face don't usually become seized to the barrel extension flange.
This is why/how you can shear an index pin by using upper receiver vise blocks to remove/install a muzzle devise even though the barrel nut was properly torqued to spec. The friction clamping the flange is less than the friction between the threads of the barrel nut and upper receiver.
I have guys that work for me that could tear up an anvil in a sawdust pile with a rubber mallet
With a little judgment and proper technique any of the barrel installation methods can be successful.
and without it you can make a mess of something as simple as installing a receiver extension.
I have guys that work for me that could tear up an anvil in a sawdust pile with a rubber mallet
With a little judgment and proper technique any of the barrel installation methods can be successful.
and without it you can make a mess of something as simple as installing a receiver extension.
I know people like that.
Iv used antisieze the upper delron block
And hand turned the nut on and off the upper with out the barrel on it
Sent from my SM-G900P using Tapatalk
Let's assume seized means that the threads of the receiver are fused to the threads of the barrel nut such that any applied torque to the nut creates a tendency for the entire receiver to rotate. With an unsupported receiver that rotation is largely opposed only by the indexing pin (some opposition is created by friction between the receiver face and barrel extension shoulder). With a supported receiver most of the rotational opposition is taken by the supporting fixture. With a supported receiver the only force directed through the pin is the result of the rotational tendency created by friction between the barrel nut and the barrel extension shoulder.
Isn't the point of the reaction rod that it locks the barrel in place and prevents it from turning inside the receiver? It seems like that would isolate the stress on the pin, unless the barrel extension starts to unthread. Maybe that is what happens. I'd like to see an example of one that has done this.
I use aluminum barrel blocks. But some people don't like having to remove the aluminum marks left on the barrel after wards.
Isn't the point of the reaction rod that it locks the barrel in place and prevents it from turning inside the receiver? It seems like that would isolate the stress on the pin, unless the barrel extension starts to unthread. Maybe that is what happens. I'd like to see an example of one that has done this.
You understand that the barrel nut is threaded onto the upper receiver, right? To 'properly' loosen the barrel nut, you secure the upper receiver (male threads) and apply a rotational force to the barrel nut (female threads). If you use a Reaction Rod to secure the barrel instead and if the barrel nut & upper receiver are seized (or over torqued) the entire assembly (barrel nut & upper receiver) will rotate, putting pressure on the index pin because it is being held firmly in place.
I'm not saying it can't be done that way but it's not the "right" way to do it.
Think of a nut and bolt with a large washer in between. To remove the nut, wrenches are placed both on the nut & bolt. You don't secure the washer in a vise and just loosen the nut. If the nut & bolt are seized, they will just spin on the washer. You need to apply a direct rotational force on the female threads (barrel nut) and secure the male threads (receiver) & not the medium held in between (barrel).
IMO, a Reaction Rod is only properly being used when installing/removing muzzle devices. Not that they won't work for removing barrels but it's not really correct the tool.
I use aluminum barrel blocks. But some people don't like having to remove the aluminum marks left on the barrel after wards.
The aluminum marks can be avoided and a better grip on the barrel can be achieved by putting something like leather or those blue paper shop towels in between the blocks and the barrel. Anyways, using barrel blocks for barrel nut installation/removal can lead to sheared index pins as well with the added possibility of potentially loosening the barrel extension.
The aluminum marks can be avoided and a better grip on the barrel can be achieved by putting something like leather or those blue paper shop towels in between the blocks and the barrel. Anyways, using barrel blocks for barrel nut installation/removal can lead to sheared index pins as well with the added possibility of potentially loosening the barrel extension.
I imagine non of the methods are with out risk.
titsonritz
01-04-16, 23:07
https://www.m4carbine.net/showthread.php?177352-Wrench-and-vise-block there are additional links in this thread.
Yes it happened. Key word was OVERTORQUED barrel nut without any anti-seize and the barrel nut was seized to the upper. Having said that I have done well over 500 uppers since I have had it and that has been the only issue thus far. You do have to be smarter than your equipment and what you are working with.
There was a picture here not two weeks ago of a sheared pin. Also I believe Iraqgunz said he had 1(one) shear upon dis-assembly of a highly over torqued nut.
It's pretty well known that it can happen.
Slvr Surfr
01-10-16, 14:40
For muzzle devices, I use barrel vice blocks. For barrel nut or handguard install/removal, I use the reaction rod.
No issues with either. Before buying the barrel vice blocks, I used the RR on more than one occasion, and had no issues. As IG said above, you have to be smarter than the equipment you are using.
This barrel vice block from brownells has blue rubber that leaves little to no marring on the barrel.
http://www.brownells.com/gunsmith-tools-supplies/rifle-tools/barrel-tools/scg-ar-15-m16-accu-grip-barrel-vise-jaws-prod12799.aspx
Robb Jensen
01-10-16, 14:48
I've removed and tightened 1000s of bbl nuts using a Geissele reaction rod and haven't sheared an index pin but also don't torque past 80ft lbs. I prefer not torquing bbl nuts past 50-55ft lbs when possible.
I have used those as well, and in many cases the barrel rotates or twists. It also doesn't work with all profiles from what I have seen.
For muzzle devices, I use barrel vice blocks. For barrel nut or handguard install/removal, I use the reaction rod.
No issues with either. Before buying the barrel vice blocks, I used the RR on more than one occasion, and had no issues. As IG said above, you have to be smarter than the equipment you are using.
This barrel vice block from brownells has blue rubber that leaves little to no marring on the barrel.
http://www.brownells.com/gunsmith-tools-supplies/rifle-tools/barrel-tools/scg-ar-15-m16-accu-grip-barrel-vise-jaws-prod12799.aspx
jackblack73
01-10-16, 15:39
For muzzle devices, I use barrel vice blocks. For barrel nut or handguard install/removal, I use the reaction rod.
No issues with either. Before buying the barrel vice blocks, I used the RR on more than one occasion, and had no issues. As IG said above, you have to be smarter than the equipment you are using.
This barrel vice block from brownells has blue rubber that leaves little to no marring on the barrel.
http://www.brownells.com/gunsmith-tools-supplies/rifle-tools/barrel-tools/scg-ar-15-m16-accu-grip-barrel-vise-jaws-prod12799.aspx
The problem with barrel vice blocks is they aren't useable with a lot of configurations, like extended handguards or my 11.5" with 10.5" handguard.
Powered by vBulletin® Version 4.2.5 Copyright © 2024 vBulletin Solutions, Inc. All rights reserved.