I bought the 6940 for the purpose of installing a top-tier barrel, knowing it had a Colt-proprietary barrel mounting system. I have built and worked on standard AR's, and have all the necessary tools and skills for most any standard AR work. But before I start buying parts and special tools for this project, I would appreciate the experience of those who have actually done this. I understand some feel the available 6940 barrel tools may be of debatable quality, but have little other knowledge. Thanks in advance for anything the experts on this board may offer.

Good luck with the whole proprietary barrel extension.

Has anyone ever done what I'm considering doing?

I've considered swapping my 6940 barrel out, but it doesn't need it yet.

It doesn't look like it's a super pain to do, but I've never done it so I have no idea on the level of difficulty here.

That tool is expensive though.

Apparently there has been a post (ETA: related to) this topic...

Another member did a tear down...LINK and then had his barrel cut...LINK...pictures are down.

I didn't realize this post was in the Precision Rifle section, it should probably be moved?

The object of this project is to build an ultra-accurate, long range, semi-auto rifle on the most stable semi-auto platform possible. And to obtain input from people who know accuracy front to back. Figured if anyone had done this fairly difficult barrel installation it would be someone on this board. That's why the post is here.

Gotcha.

I don't know man, I've been looking into this and it really seems like a PITA.  ETA:  Lots of unique parts here, PITA in that sense.

I pulled my armorer's manual out and went to that section and it is pretty straightforward...remove rail section, insert tool, twist, and pull out.  Installation appears simple too.  But I'm sure that appearances are deceptive here.

Of course...no specifics on the barrel itself.  The links I posted above seemed to indicate there were some differences and you couldn't buy a regular barrel with standard extension (duh).

Here's another LINK to a discussion about it and SA's response.  Apparently, at least in 2011, Specialized Armament had to do a whole bunch of BS.  I don't know if that has changed though, that was 5 years ago.  (If hot linking to that site is a nono, apologies)

Thanks. I may be ahead of the cool kids in wanting to do this. Seems with the stability of the 6940 system as a starting point it should turn into what I want to build but apparently none of the primo barrel makers are yet supplying a barrel with the proprietary extension installed. I actually don't want to pioneer that task.