If your gas tube is THAT fouled up, you have a serious problem. We have seen, MAYBE, 10 gas tubes that needed to be throated or replaced in the last 4 years, and all of those have been SWAT team guns....

For cleaning the gas tube of "normal" build up, a common pipe cleaner and some normal solvent works great, followed with a couple of blasts of compressed air just to clear it out.

If your gas rings are worn, that is a MUCH more common problem...

JD

 

I owned and shot my 1980 vintage Colt SP-1 for 20 years before I even knew that I was supposed to clean the gas tube. I must have had several thousands of rounds (mostly my own re-loads) through that AR by the time that I first cleaned the gas tube. Now I make a point to do it every year or so. Geeze, this is really NOT an issue, but IMHO it is a bunch of BS to sell gas piston AR variants. It's just not that neccesssary! Never had probelms with the gas rings either!

 

My brother bought one of the first civilian Colt AR-15's in the 1970's. He has never cleaned his gas tube or replaced the gas rings. I have never known ANYONE who has had to clean the gas tube on a semi-auto AR-15 because of a carbon build-up. It's probably a good idea to spray it with gun scrubber or run a pipe cleaner through it from time to time, but I don't see it as a necessity for continued function. Full auto M-16's & M-4's are a different story.

 

All I have ever done is spray brake cleen down the tube every 4-6 months. I have sent thousands of rounds through 4 different variations of AR's that I own and have never had a gas tube issue.

 

As most have already stated, strange to have probs there, unless the ammo was extremely dirty to begin with, or the tube has seen a couple lifetimes of hard use, or someone has been playing Spec-Ops/Delta Farce and going swimming in the local pond with their AR....

Just squirt some gun scrubber or brake cleaner or some type of safe solvent down into the tube, let it sit for a while to work on whatever is in there, use a couple pipe cleaners to scrub it out, spray some compressed air through to blow out any residue. I think there is a kit put out by some of the bore cleaning guide folks now...Dewey, Kleenem & Howe

Slo

 

There's, also, a small gap in the, 'bolt' (or gas) rings. Those gaps should never line up. Ideally, you want them set 90 degrees apart from one another. Check to see how the stock buffer and spring is functioning, too.

 

Gas ring spacing is a MYTH

To the OP,
Other things to check...

These were quoted..

Check for a loose gas key on the bolt carrier. Every time you field-strip your weapon, simply grasp the bolt carrier and twist the carrier key by hand. If loose, it will move, and any movement indicates the gas seal is broken. The repair is simple (have a trained armorer do this): Unscrew the carrier key by removing the two cap screws. After removing the bolt assembly, clean all surfaces with a non-petroleum based degreaser, apply Locktight 640-green color to sleeve and bearing (or red color 272), and reassemble. Tighten down hand-tight with an Allen wrench and let cure overnight for best results. You can then restake the area above the cap screws.
Make sure the three stainless-steel gas rings located on the bolt are unbroken and unbent. Some claim all three gas-ring gaps must be in line to prevent gas blow-through and short cycling. In practice, however, I’ve never seen this occur.
Other than wear, most damage to gas rings occurs due to improper cleaning. Using stainless-steel brushes around the gas-ring area can bend or tear out gas rings.
Check gas rings for wear by removing the bolt carrier group from the rifle and standing the bolt on its face with the carrier vertically above it. If the weight of the bolt carrier causes the bolt to collapse inward, replace the gas rings. Replace all three at the same time.

Quoted from Jeff Chudwin @ Law Officer.com

Also, a link with alot more helpful info...

AR15BARRELS.COM - Randall's description of AR gas operation and how everything works in harmony

Slo

 

Thanks all, I git the rifle today and looked it over. It is a Olympic Arms 6.5 inch "pistil" with a collapsible but stock. I checked the gas rings and found one was about 3/4 gone, and the other two were not in good shape. I then looked at the gas tube and found it has broken off the front sight gas block. I don't know how this happened but it is a SWAT rifle so who knows. I have a call info the CO to see if they can get me a new gas tube. As long as the gas block was not damaged I think I can put the new gas tube on and be ready to go. I will keep you all up dated but it might take some time, the CO is talking 3-4 months out for any parts for there rifles. I will be doing some other looking to get the part faster. If anyone knows of a good place to look, IE Brownells, Midway and such let me know. Thanks again, BigGuns

 

Gas ring spacing is a MYTH

To the OP,
Other things to check...

These were quoted..

Also, a link with alot more helpful info...

AR15BARRELS.COM - Randall's description of AR gas operation and how everything works in harmony

Slo

Come on, Slo! (I'll bet they don't call you that for nothing, huh.)

If you're going to call me wrong on something at least don't use a reference article that clearly verifies what I've said.

Pay more attention. Things are going to get a lot tougher from here on out! OK!

 

Come on, Slo! (I'll bet they don't call you that for nothing, huh.)

If you're going to call me wrong on something at least don't use a reference article that clearly verifies what I've said.

Pay more attention. Things are going to get a lot tougher from here on out! OK!

The reference article and link were for the Original Poster, hence "To the OP".

That needing to be clarified shows that only one of us is SLOW.

Any gunsmith, AR armorer, gun writer, etc. out there will tell you the same thing about gas rings. But who am I to tell you any different.

I am Slo.

 

I used to line the rings up on my M-16 in the army to see what would happen.


NOTHING is what happend. So I dunno i only have thousands of rounds down an AR with 8 years of qualifing in they army 40 out of 40 99% of the time. Even went to the US ARMY armour course and scored the highest score in the class. I even field stripped an M240B faster than guys that had been carrying it for years.

Oh well. Has anyone ever thought of using something like GM top end engine cleaner in a gas tube. It is specificly made to eat away carbon build up. I know G21 it is not ment for cleaning guns with right. Well tell that to the guys that are using it on $5000 bench rifles. Don't even go there with me. You will not win that fight and you will look stupid in the process.

 

"Even went to the US ARMY armour course and scored the highest score in the class."

So help me out brother, why would a gas tube break off at the gas block on this gun. I can not see any signs that someone hit it, so what gives. I don't think the gun could get so hot that it would burn off. I have not taken it apart yet (the boss whats me to get parts first) so I can give you more that what I can see with the hand guard on. I will put up some photos when I get it apart.

Second Q is any suggestions on putting the gas block back on. Getting it off looks OK and I have found videos showing that. I have not found any videos showing how to put it back on. Do I need to worry about the front sight alignment, do I need new pins or use the old ones, do I need to mark the block so I can line it back up correctly. Any tips would help. Thanks

Any by the way, I have went to the Colt armour school and they even told use we did not need to line up the gas rings.

 

K23B Gas Tube

I don't know if you found why the gas tube was broken, but my guess was that it was ate up by the high pressure. The system is very short and runs very high pressure and very high temp, I have two and one of them has a hole eaten through the tube opposite the regula gas port. The gas will deteriate the tube after 7 - 10K. Keep gas tubes for those in stock.

 

Listen

Yes the gap is a myth, if the blowback is in good shape and properly staked it will only have one position on the bolt carrier. As metioned above if it is loose you need to have it fixed and recomended you need an armor to do it right. As for the gas tube blockage; all the ideas are very good ones. I actually run a wire down through the badly blocked ones followed by a brush atached to the wire. this along with good solvent will remove any build up. after that a good hight preasure air blast ensures good air flow. on normal cleanings I simply just use a solvent designed for carbon build up and flush for a while in a parts cleaner until clean. then air blast dry.
on my personel weapons and I have had AR's for long time I have never Had to ream a gas tube ever, only those people who never heard of cleaning after everytime you take it shooting, have I had to ream a tube. LOL

I worked on the F/A 18 and the blast deflector in the nose in front of the windsheild gets build up from the fireing of its guns. but we are talking about a Vulcan style weapon and that deflectore gets only mild cleaning. they have to be sent to NDI for cleaning; in order to remove the Carbon and Copper build up. The AR gas port works in almost the same way. So Cleaning is very important after every shoot. Im not saying you dont do that but I was merly pointing out a fact.

 

its a moot point now, as youve already found your problem, but fwiw, if a gas tube truely was that bad that it was impeeding function, i dont see why anyone would want to spend hours upon hours soaking and brushing over and over again to get it completely cleaned, when you can throw a new one in in 10 min.

afa you other questions (post 13) i may have missed it, but is this a one piece free float hg with a std a1 type sight? if not, i cant see why removing the hg is such a big deal, or why you would even attempt to remove the fsb to change the gas tube. even if it were, theres a good chance you could change teh tube without removing the hg, depending on where it is broken.

 

gas tubes can fail if they get VERY VERY hot through extended sustained fire. usually dont see that in the civilian world. gas tubes are also cheap around 10-14$ if the gas tubes in one of my 5 AR uppers even looks like it has a hint of a dent or ding i toss it and replace it. its not a big deal.

if you got a blockage run a long pipe cleaner through it. if its not dislodged easily just replace it.

 

The gas tube

The Gas tube is a very weak parts of the AR and is one of the cheapest parts to fix. But we all know to if you custome your AR with free floating rails and other parts that intermingle with the tube you can damage the tube and cause it to fail. freefloating rails can bend the pipe, bad powder can clog any weapon (expecially old world war 2 amo), improper maintinace can also damage gas blocks and tubes, and bad handling of the weapon can damage a tube. So there is a solution to the gas tube debate. If you keep having problems with the tube. simply replace it for a piston assembly and have no more problems.

The piston assembley replaces the tube and reduces buildup in the breach area I recomend doing that if you get the chance. I think you will like it totally.