I thought that it would be relatively easy for a "Gunsmith" to install a free-float tube on my AR.  It was not.  Now I am in serious trouble because the barrel extension of all things is ruined.  Can the extension be replaced...indexed and headspaced properly... or do I need to replace the complete barrel assembly?  Any help?

Usually the extension can be replaced and the barrel headspaced, but I'd recommend you have a competent AR 'smith handle the job...

Kurt at KKF is the AR Wizard... he'll do ya right... [;)]  You can find Kurt's forum here on ARFcom in the Industry section...

How the heck did that happen???

Ouch!

I'd definitely be HeartBroken...

Good Luck.

MM419

Most gunsmiths don't know $#!+ about the AR15/M16 rifles.  If you need any specialty work done, by all means, seek out someone like Kurt that specializes in tactical rifles.

[size=6][red][b]I[/b][/red][/size=6] can install a free float hand guard/tube.  

Your [green]gun smith[/green] ain't no gun smith.

Thanks for the input, guys.  I have been recommended to give Kurt a call by others and it is encouraging to have you recommend him also.  I will give him a call.  To make a short story long...here is what happened.  I disassembled the barrel as far as I could with the tools I had.  I could not loosen the barrel nut so off I went to his shop.  The barrel nut was so tight that when it finally broke loose it sheared the index pin in the extension off.  Did not seem to damage the receiver but the extension actually got tightened slightly in the process so now the indexing of the gas port and front sight is off by a few degrees.  I have since learned that the barrel nut can sometimes be very tight.  Soaking them in Kroil for a while then applying a little heat will usually break them free.  I guess I can't be too hard on the guy because I stood by and watched it all happen.  Life is a learning process...Sometimes painful.  

Some where, some one, was talking ca ca about the barrel installation procedure.

Maybe they were right.

Sounds to me like no break free lube was installed on the threads.

Okay, I wouldn't be too hard on the guy either. I've been through that process. I had a nut that was on so tight. I tried everything. Soaking in penetrating oil,and heated it with a blow torch. It would NOT come off of there (maybe it was originally overtorqued, or no lube was used, or both). I finally had to send it back to the manufacturer.  Who knows what they did to fix it, maybe they have magic tools, or maybe they screwed up the extension too.

I recently heard (after I had just sent the upper back) that if you put it in the freezer overnight that that will usually allow the metals to retract and it can be seperated. I would have like to have tried it, but it was too late. Oh well, another tool to throw in the tool box of "live-and-learn".

Was the gunsmith using a barrel vis or receiver block ?? cause from going through a handguard install myself I can see that if that nut is real tight and your holding the barrel all the force put on removing the nut will stress the extension and index pin. Cause since the nut is tight on the threads, the receiver also wants to turn with reference to the barrel, results in lots of force on the index pin.

I am using a receiver block, all the pressure is applied to the receiver only, the barrel and extension are just there for the ride. I really had to crank on my wrench to loosen my barrel nut (tightenned and removed it a few times)and no damage whatsoever on the barrel.

Good luck,

I think Brownell's sells a can of "super cold spray" that can be used like this. The application I heard for it was stuck choke tubes in shotguns, but this is along the same lines.

I have had to cut barrel nuts off with a Dremel tool.

The guy was using a barrel vice only...maybe it would have best to use the receiver block.  After this happened I have kicked myself in the A** multiple times.  I am glad to hear that I am not the only one that has had a problem in this area.  KKF comes highly recommended and I am now confident that I do not have a totally ruined barrel.  Thanks all.

I, too, am trying to remove a barrel extension. I have a de-milled barrel and want to salvage the extension.  Looked to be no problemmo. So I took a 5/8 deep socket and milled a couple slots in it with a 1/4 inch end mill. Put an old 16 bolt in it and welded it all together to make a neat-o tool.  Thought it would be a slam dunk til the barrel turned in my vise.  So I took a pipe and cranked the vise tighter.  I mean REAL tighter !   It still slipped.  So I welded a ridge on the scrap barrel to stop that movement.  That worked. The barrel didn't turn anymore.  But the extension would not move. So I cranked up the air to the impact wrench and laid onto it.  Sheared the bolt off from the socket !  I think my wrench generates about 400 FtLbs of torque. So now you know what a bolt will (won't) take.   So at this point I still have an extension that's on the barrel. I'm assuming that it IS a right-hand thread, isn't it ?

Any thoughts ?

Roger

Roger - What the &^%$ are you trying to do... [shock] Got quite a [ROFL2] out of your story, guns should be fun to play with, but this is too much.

First, why are you trying to salvage a barrel extension ? When you order a barrel it is my understanding the extention is already mounted to the barrel. That way you have no worries with headspace setting.

Second, the part removal procedure that is currently being discussed is the removal of the barrel nut that secures the barrel (at the extension area) to the upper receiver (ie the rifle).

I coudn't tell you how the extension is fitted to the barrel, I would have no need to remove it from the barrel.

Goodluck

[added] After a forth read, I finally figured out the tool you made, cool idea, but none the less kinda useless procedure to do in my opinion

Furet
Fella I work with wanted me to remove  it for him. As I understood it, I would have needed to do this anyhow, since I'm going to rebuild my upper with a flat-top receiver. So this  'learning experience' is proving valuable. (plus, it's HIS scrap barrel, bolt and socket. I only provided the Bridgeport and welding and impact wrench)

You can see, now, that I really don't know what I'm doing, as the AR I recently 'built up' is essentially put together without having to make any major changes. I haven't taken a barrel  off of a receiver yet so I didn't know what is involved.

I didn't know that the extension is not normally removed. I now get the impression that there is only a nut holding this assembly into the receiver.


Roger

Roger - I am at my first barrel change also. Learning as I go ... The barrel extension is fitted to the barrel and sets up the proper head space. If you look at your barrel and extension there is a ring of a larger diameter where the barrel meets with the extension, that is the area that meets with the upper receiver. The nut is on the front end of that and holds the barrel/extension in place. Actually, look at the tacked thread at the top of this forum, there is one which is "AR15 exploded diagram", you might be able to see how it fits together.

On a standard forend the nut is under/part of the delta ring, on free float tubes the nut is usually a big ring with holes in it. Other than my torquing issue, changing barrels is a joke. You will need a barrel wrench, receiver block and punches. For some the torque bar is optional.

Good luck