Alternative method for barreling an AR?

[wash]

I'm assembling my first AR upper soon and I'm looking for tools.

The standard method uses a receiver block that surrounds the upper or a Panther Claw that uses the takedown pin holes to hold it.

Neither of those methods seem very good to me.

Then I saw some YHM picatinny rail vise jaws and I thought that's a good place to grab the upper close to the bore centerline but then I found something even more appealing to me:

http://www.brownells.com/.aspx/sid=53686/pid=27452/sku/AR_15_M16_Barrel_Extension_Torque_Tool?utm_medium=shoppingengine&utm_source=googlebase&mc_id=10000&gdftrk=gdfV21820_a_7c187_a_7c745_a_7c080000637_d_080000637_d_116

That with a good barrel nut wrench seems like an ideal way to take the torque off the upper (beyond the actual threads).

I think I'm going to go that way instead of the other methods unless I hear of some reason not to.

If you've used any of these methods, give me your thoughts please.

Thanks.

[a308garand]

The clamshell blocks that fit around the upper receiver are o.k. for regular barrel jobs. Its when you go overboard with the torque wrench that damage happens. Don't go above 80 lbs of torque to get it tight.....

Another way to mount the barrel is the old barrel blocks. It holds the barrel and does an o.k. job of removing/installing barrels without the clamshell type tools.

http://www.brownells.com/.aspx/sid=29522/pid=12470/sku/Barrel_Vise_Jaws?review=1

[wash]

Well, my upper is an ASA side charger, so I don't want to take a chance on it not fitting the clamshell block.

It looks like the clamshell even costs more so using the barrel extension lugs seems like it would be more compatible, cheaper and it seems to me that it might even be better than OK on a barrel job.

[BSlacker]

Where is the turning torque stress put with this system? It seems to me that it puts a lot of stress on the barrel pin. Wouldn't you be using the barrel pin to drive the upper receiver around to tighten the barrel nut. Most places will let you return an unused tool like a receiver block. I bet the folks at Brownells could tell you if the block would fit your upper what does the OEM use to install barrels have you asked them.
This will work but will it damage the pin slot or pin is my question. The receiver has the threads and it has to be driven by something and in this case it is the barrel pin. The pin was for location not torque stress to install the barrel. Seems to be using the pin incorrectly. Would your front sight come out straight?

[wash]

That's the $10,000 question.

I don't see how any other common method of tightening the barrel nut can avoid putting that shear stress on the pin because the barrel nut is always going to try and turn the barrel in the receiver (or the receiver around the barrel depending on how you look at it).

I've read some people suggesting to clamp the barrel in one vise and hold the receiver with a block or a Panther Claw but I think that setup would twist enough to put all of the torque right back on the barrel pin and twist the upper at the same time.

The only method to remove the shear from the pin that I can come up with is to attach a barrel block clamp to a female picatinny section that would tie the upper to the barrel, then torque from that clamp to the barrel nut. That tool would have to have very low clearance to the barrel nut wrench, tight tolerance and a seperate tool for each barrel profile you choose. It could be done but it's a lot of work and as far as I know, no one does it.

[Josh3239]

I've used the DPMS panther claws on several uppers, including my ASA upper, and never had an issue. I wouldn't be surprised if in the event of over torquing, the del-rin breaking before the AR.

[a308garand]

As things start getting super tight, the index pin can be forced to dig into the upper receiver cutout- bad news because you get a canted barrel. Either the two vise method, the barrel blocks or even the clam shell works for this job as long as you don't go over tight. Those tools cost more than the $27.44 for this barrel extension tool, it sounds like a good deal.

I don't know anyone using this tool, but I think thats what we need to hear....Who has used it and how well did it work out?

addedops the barrel blocks are $22.15 not much less than the extension tool

[BSlacker]

I don't see how any other common method of tightening the barrel nut can avoid putting that shear stress on the pin because the barrel nut is always going to try and turn the barrel in the receiver (or the receiver around the barrel depending on how you look at it).

In the common method of barrel nut tightening one would use a little anti seize or grease and as the nut came to the barrel shoulder it would push the barrel into the receiver and take some force. The pin would only take a small amount of torque compared to driving the receiver into the barrel nut. The pins job is holding the barrel in place until it has the nut tight and is pressed into the receiver and it is designed to do that.
Using the barrel extension tool the pin is the force point and takes all the stress. As the nut tightens it will put more force on the pin which is the opposite of the common method. I think it will work most of the time but if it doesn't it could be costly. Just call and ask the OEM how they do it.

[Roccobro]

Has anyone called or asked Randall (ar15barrels) yet? I'm sure he has an answer, one that everyone can trust.

Justin

[maxxrange]

I believe the US Military Armorers use the aluminum barrel blocks for installing/removing barrels. That and a mil spec grease which is quite inexpensive.

The vast majority of barrel instal problems occur when the first time assembler wants to really torque the barrel down so it "won't go nowhere" and does not own a torque wrench. The manual says 35 - 50, with 80 at the threshold of nut failure or upper receiver tweak.

The last one I did, I had the gas tube line up perfectly at 38 lbs. I left it and have had no problems at all. Tighter is NOT better. Look at the nut and the threads closely which are aluminum. Those are not 80 ft pound devices.

It is much more important to use the correct barrel nut wrench. Especially with free float nuts. Yankee Hill Machine, Daniels Defense and Viltor all have different torque values and in some cases, proprietary wrenches that you have to use due to an oddball design. Some have aluminum barrel nuts. Put over 50 ft pounds on one of those and they fold up like wet pretzel. Dont ask how I know this.

[wash]

I think that using a barrel block with a barrel nut wrench will still put a similar amount of torque on the barrel pin. If you think about it, whatever force you put on the barrel is countered by the barrel nut wrench (through the wrench to the nut, through the nut to the receiver and through the receiver to the pin and through the pin to the barrel), the only difference between the two methods is where the torque is applied to the barrel. The barrel isn't going to twist so essentially it's the same thing. What I like about using the barrel extension lugs is that a barrel block can mar the finish of a barrel and no one expects a barrel extension to be pristine...

Also, clamping on a barrel block takes time, tightening your barrel nut wrench in your vise, dropping in the hand tight barrel and upper and then inserting the barrel extension torque tool is really easy.

I agree on the level of torque, keeping it reasonable is the right idea. One other thing I like about the barrel extension tool is that you can get your torque wrench exactly on the axis of rotation, no calculations to determine the actual torque with an offset wrench.

The rail I'm using is a Samson that uses the standard steel barrel nut. I expect it will go together smoothly. I don't know what the thread diameter is but I expect that the 7075-T7 aluminum of the receiver should be able to handle quite a bit of torque as long as it's concentrated in the threads and not across the whole receiver.

I hope I can nail 50 ft/lbs. Tighter is less likely to loosen and with grease in the threads I would rather be at the high end of the range.

[DREADNOUGHT78]

I use the vise block with the takedown pin mount and a DPMS AR Multi wrench. Built 30 or so uppers with it and the only time I have ever had a problem is when I over tighten a barrel nut. I have installed YHM,D.D.,Troy and a few other rails and they all have installed with zero issues. Torque ranges very for each different nut and upper receiver. Just get the barrel nut over the reccomended torque range and snug till you can align the gas tube. I have never stripped a barrel extension pin or broke a receiver. When I built my first upper a few years ago I had none of the AR tools yet I still managed to get my upper together and it still running like a champ.


My friends kitchen table a few years ago.



We must have bought 40 or so of Matt P's barrels!

[ar15barrels]

I'm assembling my first AR upper soon and I'm looking for tools.

The standard method uses a receiver block that surrounds the upper or a Panther Claw that uses the takedown pin holes to hold it.

Neither of those methods seem very good to me.

Then I saw some YHM picatinny rail vise jaws and I thought that's a good place to grab the upper close to the bore centerline but then I found something even more appealing to me:

http://www.brownells.com/.aspx/sid=5...80000637_d_116

Do you realize that the tool linked above is best used to INSTALL barrel extensions?
Holding the barrel by the extension is much akin to just holding the barrel with vise blocks.
Neither method is good for the receiver.

You are missing a key piece of information in your analysis of the DPMS claw.
The DPMS claw supports the receiver by the inside.
It only uses the receiver's pins to keep the receiver on the block.
It is not putting stress on the receiver at the pins.

I have used every receiver retention method available and the DPMS claw is the best there is.

[ar15barrels]

Where is the turning torque stress put with this system? It seems to me that it puts a lot of stress on the barrel pin.

Yep.
The tool above puts all the barrel nut torque against the barrel indexing pin which helps to damage the receiver's indexing slot and the final results often include a crooked FSB.

[Roccobro]

*long sigh* I can sleep easy now that Randall has posted.

Justin