How do I get this M1A gas cylinder plug off?


November 1, 2007, 04:58 AM
I've just finished doing the initial cleaning of my new SA M1A Loaded. Everything went fairly well except for my attempts to remove the gas cylinder plug, which were ultimately futile. Despite using a gas cylinder wrench, takedown tool, and a significant amount of effort, the thing wouldn't budge. I was trying to turn it counter-clockwise as viewed looking into the muzzle, so unless the screws are reversed for the gas plug, I was going the right way. Also, the gas spindle valve is set to the grenade launcher settings, although I don't think that would make a difference.

I know that the gas cylinder and piston doesn't have to be cleaned every time, but when I do ultimately need to clean it, I'd like to actually be able to do so! Does anyone have any tips on how to get a recalcitrant gas cylinder plug unscrewed?

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wayne in boca
November 1, 2007, 06:38 AM
Use penetrating oil,like PB Blaster or Kroil Oil,put some in the vent hole on the bottom of the gas cylinder and the end by the hex nut,let it sit overnight,try it again.Make sure to clean out the oil afterward,the gas system should be run bone dry.Try orienting your gas cylinder wrench with your combination tool so that you can squeeze them together like closing a pair of scissors.Once you get it off,use a dab of grease or anti-sieze on the threads so it never gets that tough again.In extreme cases,I have heard of people locking the gas cylinder in a padded vise and using a 3/8 socket wrench with a cheater bar to remove them.Good luck.Do you swear well?

November 1, 2007, 10:48 AM
Got a raw hide mallet? Maybe a hard plastic mallet? I suspect you are going to have to wack the gas cylinder wrench with something fast and hard like these mallets. Don't use something heavy, you want a fast hard shock.

Also, you can use a standard six sided socket wrench on the end of the plug. I forget, might be a 3/8", I forget. Just check. And don't use a 12 point socket, you will round the corners. Soak as per Wayne's instructions, and give the wrench ends a couple of wacks, to break stuff up, and then use a socket wrench. Do not forget to use your gas cylinder wrench and apply an equal amount of reverse torque. You don't want to shear the gas cylinder out of its splines.

I don't know who told you not to clean your gas cylinder and gas pistol each and every time, but that is something I do. Of course I am not shooting my M1a every week, and I live in a hot humid environment.

I was shooting CMP week, living in a hut, when a shooting bud came over with his State M14. It was malfunctioning. He had been told to never clean the cylinder or the piston. Well that gas piston was full of carbon. Used my cleaning drill, carbon poured out like pepper from a pepper shaker. The gas piston was also heavily pitted. Like deep round pits. Made sense that the gun was opening too soon in the pressure curve, the gas piston was clogged.

I remove the lock plug, remove the pistol, leave the gas cylinder on the barrel, and swap the insides with GI bore cleaner. And I clean the piston off. I have never had a problem.

On my M1 Garands and M1a's I install the gas cylinder locks with Permatex Antiseize. Got the stuff at an Automotive store, the grease is used on intake manifold bolts and items like that. Everyone needs to use the stuff on their gas cylinder lock screws to advoid what you are going through.|/images/ProductPhotos/80071.jpg

Mark whiz
November 1, 2007, 12:06 PM
I'm with SlamFire - I clean out my gas system anytime I've fired over 20 rounds thru the gun. I've had accuracy affected with less than 100rds fired and no cleaning.
An anti-sieze product is a good idea, just make sure you use only a small quantity of it and that it is on the treads only - you definitely don't want to get any on the piston or in the cylinder itself. Personally, I use a silicon "nipple" grease that I also use on my black powder guns - it's not as coarse as an automotive product and easy to control the application so there is little risk of getting it on the piston.
Once you reassemble the system, don't torque the bolt really tight - that'll sure help getting it off the next time. 5 to 10 ft lbs of torque is all that is really needed.

General Geoff
November 1, 2007, 12:45 PM
It was a real PITA to get the gas cylinder plug off mine initially as well. Once off, I smeared a dab of molybdenum grease onto the threads. no problems anymore.

November 1, 2007, 01:06 PM
They plug should only be hand tight. It's easier to get off if you have a socket and gas lock wrench.

November 1, 2007, 02:02 PM
Penetrating oil (not WD40)

November 1, 2007, 02:33 PM
I just wish they made a gas lock wrench that would fit properly. I have two different wrenches and neither of them fit the gas cylinder locks properly on any of my M1As.

November 1, 2007, 02:45 PM
My Sadlak wrench works like a charm. I don't however use the takedown tool. - I use a box wrench. The first time I took my plug out it was tight, so I hit it with a touch of heat from my mini torch. Popped right off. I'd be curious to know where the "hand-tight" method comes from. I heard, (and follow) from an M-14 Smith that the GP should be torqued to 15lbs.

November 1, 2007, 03:14 PM
Thanks so much for all the helpful advice. Also, I'm glad I brought up the gas cylinder cleaning issue, since it seems like I was mistaken about how often it should be looked at.

About how long do you recommend letting the penetrating oil soak in? You'd pretty much need to store the gun muzzle-down to let the oil soak into the threads from inside the cylinder, right?

Finally, do you think it could make things any worse to shoot with the seized plug? It's possible there might not be time to fix things up before this weekend, which was when I'd planned to take the gun to the range for the first time.

General Geoff
November 1, 2007, 03:17 PM
pull the op rod and lock it back. then tilt the rifle back and forth, from vertical to vertical (muzzle up, then stock up). You should be able to hear the gas cylinder sliding back and forth. If so, you're fine.

November 1, 2007, 03:24 PM
I had the same problem with my SOCOM from Springfield. Springfield must employ a gorilla to tighten them, as I've read lots of other people having problems.

Use a hair dryer to heat it up, spray it down with WD40 after it heats up, heat it up again, then try to take it off again.

After you get it off, degrease the gas cylinder and put some grease on the threads. You'll be good to go.

November 1, 2007, 03:39 PM
MassMark, most people I know don't take a torque wrench into the field.

FM 23-8 states "Replace the gas cylinder plug and tighten it securely with the wrench of the combination tool."

November 1, 2007, 06:53 PM
Heck guys, I crank down on my gas cylinder lock plug, I make it pretty tight. Not insanely tight, but pretty tight. Hard to quantify without a torque gage.

I use that tiny GI wrench I guess I am getting at least 10 foot pounds, maybe more. I was told that 25 footpounds was all the torque you could get using a standard 3/8" rachet, and this wrench is shorter.

Having my gas cylinder plug come loose during sitting rapid during the NTI at Camp Perry, and shooting a group that a small elephant could walk through, I have gotten particular about plug tightness.

Since I use anti seize, it just takes a good humpf to break the plug loose. I always use a gas cylinder wrench.

Gotta make sure you are using a GI lock plug. A friend was using a Fulton Armory vented plug, it was soft and stripped out. We tried a field repair with hay bailing string, but that did not work, and the shooter was very unhappy because he could not complete the match.

November 1, 2007, 07:42 PM
When I say hand tight, I mean as tight as you can get it with the military tool. Don't use a big, long wrench. I've see plugs that took two men and a small boy to break loose, although my favorite was someone who had used locktite. He mentioned this after I had spent a few minutes trying to get it loose with a small wrench.

November 1, 2007, 10:29 PM
MassMark, most people I know don't take a torque wrench into the field.

LOL...I hear ya - I don't either, but I do torque it at home just for S&G's...I misunderstood your definition of hand tight as well - mine would be on the ground in a few rounds if I tightened it truly by hand.

November 1, 2007, 10:30 PM
Double Tap...

November 2, 2007, 12:36 AM
The darn thing finally came off! I put a little Liquid Wrench in the gas vent hole (thanks for that suggestion, by the way; using the vent hole would never have occurred to me otherwise) and sent some more oil in through the top to meet it. After a few minutes and some light tapping to help the oil make it through the threads, an herculean effort with a socket wrench managed to dislodge the gas plug.

By the look of things, the steroid-popping gorilla in Geneseo, IL who was responsible for installing the gas plug never bothered to put any sort of grease on the threads--a mistake that has now been corrected.

Thanks for all your helpful suggestions. It occurred to me that ARs don't have this kind of problem, but then it also occurred to me that using this much force on an AR-15 would probably break it. :D

November 2, 2007, 01:04 AM
Victory is sweet!

You can break an M-1A by buggering the barrel splines where the gas cylinder fits. That's why you use the gas cylinder wrench while removing the plug.

November 2, 2007, 09:27 AM
You can break an M-1A by buggering the barrel splines where the gas cylinder fits. That's why you use the gas cylinder wrench while removing the plug.

I can believe it. The amount of force required to get the thing off would definitely have messed something up if I hadn't used the wrench.

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