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The gas system on your M14/M1A should be cleaned after roughly every 500 rounds or if you begin to experience cycling issues. If your rifle does not pass the tilt test, it may be time for a cleaning as well.

First, begin by making a witness mark on your gas plug and gas lock so that you can apply the same torque upon installation. If you have a torque wrench and set by torque, don't bother with the witness mark. You can also use a sharpie or white out.

Secure the gas cylinder with a gas cylinder wrench or a crescent wrench with a rag or tape around the jaws. Using a BAD-T1 tool, USGI multi-tool or a 3/8" boxed end wrench, loosen and remove the gas plug.


If you have the BAD-T4 gas cylinder wrench, ensure the threads are clean on your gas plug and screw it into the BAD-T4 wrench as pictured. This will give the plug a nice handle when cleaning and will also prevent it from rolling around on the bench.


Using a nylon brush and some powder solvent, clean the exterior of the gas piston and completely dry when done. I also used a bronze brush gently on the stubborn carbon build up areas and the carbon came right off without much fuss.

Once the exterior of the gas piston has been cleaned, insert it into the "D" cut of the BAD-T4, BAD-T1, Sadlak gas cylinder wrench or Smith Enterprise gas cylinder wrench. This creates a handle for the next step. Obviously, if you have neither, then don't worry, you can get by without it.


Next, clean the inside of the gas piston with a letter P and number 15 drill bits. You use the drill bits to scrape carbon from the inside walls of the piston. Lots of black dust will come out. This is normal.
Note: when performing all scraping, be careful not to remove metal from the gas system components! To avoid cutting into the metal, you can grind about 2/3rds of the cutting tips off your drill bits to prevent damage to your gas plug and piston. I then smoothe the grinding with an Arkansas stone.




Now use the letter "O" drill bit on the gas plug and do the same...


Use a bronze brush with powder solvent to clean the inside of the gas piston and dry thoroughly with q-tips or cleaning patches. The inside should be clean and dry




Do the same with the gas cylinder and dry thoroughly. Insert the gas piston. lock the bolt to the rear and make sure the gas piston sinks down all the way...(this means the gas piston tail is lined up with the "D" cut in your gas cylinder) (Note: all gas system components should be completly dry and free of oils and solvents upon re-assembly. Oil can be used in a pinch to get a seized gas system to work but it should be disassembled and re-cleaned during your next maintenance session)



Ensure the threads of the gas plug are thoroughly cleaned and dry. Apply some anti-sieze to the threads.


Using your gas cylinder wrench and tool of choice, torque the gas plug to match the witness mark you made before you disassembled the gas system. If you are using a torque wrench, the minimum recommended torque is 120 inch pounds (10 foot pounds) and the maximum is approximately 23 foot pounds. The popular ranges are 120 inch pounds to 150 inch pounds. Gas plug torque may affect accuracy so play around with what torque works best in your rifle. German torque is also acceptable (Good-N-Tight)


The gas components pictured have just under 700 rounds through them and they cleaned up very nicely. It was a USGI gas system with a Sadlak TiN gas piston (no groove). YMMV
 

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Discussion Starter · #2 ·
About Sadlak gas piston drill bits

I sent a PM to RightHand asking if their drill bits are modified so that they won't cut the piston or plug and this was her response:

Hi Tony

No, we do not dull the bits for piston and gas plug cleaning because the drills we supply are specially purchased with an angled tip that diminishes the possibility of damaging the piston material. A standard tipped bit has a greater possibility fo damaging the piston. The piston is 45 Rc whereas the drill is a 60Rc so I can see where the concern is but we feel the angled tip takes care of this problem. We do modify the drills we sell for installing our QD assembly post to help avoid splitting the stock.


She also recalls Ted mentioning not to chuck a drill bit into an electric drill as this will increase the chances of damaging your gas system components. This is good advice....

Thanks RightHand!
 

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I went to a hardware store last month trying to find a number 15 bit and a "P" bit and the guy trying to help me did not kow those sizes. Like they were metric or something to him.

Good information in this thread though.
 

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Discussion Starter · #7 ·
The lettered gas piston drills must be purchased from a machine warehouse like McMaster Carr or MSC Direct.

Other than that, Sadlak makes a great tool set if you have the cash.
 

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I want to try to make my own scapers, but I will have to find an alturnative to the above places. I went back to the same hardware store today and I have a line on where I need to go. Just in case, I will probably need to search the internet for those sizes. I originally thought I read somewhere what the sizes I needed were in inch measurements.

I will keep the above places in mind, Thanks.
 

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Gas Piston Question

Tony,
I am new to the M1A rifle. I bought a used rifle and followed your thread on cleaning the gas system. I did not break the gun down any further. The gas piston came out fine with just a light tap. There seemed to be a lot of carbon build up but I do not have a comparison. I got everything cleaned and dried off before re-assembly.

When I put it back together it sounds as if the gas piston is sliding back and forth inside the chamber, when the breech is locked back. When I release the breech and it closes the sound stops. Is this normal? I do not recall hearing this when I got the fun. Any information you could provide would be appreciated.
 

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Discussion Starter · #10 ·
Tony,
I am new to the M1A rifle. I bought a used rifle and followed your thread on cleaning the gas system. I did not break the gun down any further. The gas piston came out fine with just a light tap. There seemed to be a lot of carbon build up but I do not have a comparison. I got everything cleaned and dried off before re-assembly.

When I put it back together it sounds as if the gas piston is sliding back and forth inside the chamber, when the breech is locked back. When I release the breech and it closes the sound stops. Is this normal? I do not recall hearing this when I got the fun. Any information you could provide would be appreciated.

[Chuckle] What you are hearing is the gas piston sliding under it's own weight which is the desired outcome of a clean gas system. GI7

Here's a little more on what you are hearing...

http://m14tfl.com/upload/showthread.php?t=69061
 

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Called MSC Industrial Supply and the young lady answering the phone (one ring and not having to go through a ton of options) was just fantastic to work with. She gave me the link to the aircraft length #15 drill bit, took my order, and said they should be here in one day! We'll see about that. I ordered four; two for my buddy and two for me.

Thanks for the tip - I look forward to working with them for any other future tool needs.

BBBJW
 

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I got my aircraft length #15 drill bits this afternoon, less than 24 hours after I ordered them; got two, a wear and a spare.
 
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Just a question: for the recreational shooter are the drill bits necessary? My uncle (USMC 65-69) and dad (USAF 62-88) taught me how to clean the gas system with 28ga, .357, and .17/22 brushes. The 28ga for the gas cylinder, the .357 for the plug and the .17/22 for the piston. With a good cleaner, I use wipe out, it gets everything out. For the ports we use pipe cleaner. Is this wrong or just not as effective?

Thanks in advance.
 

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Just a question: for the recreational shooter are the drill bits necessary? My uncle (USMC 65-69) and dad (USAF 62-88) taught me how to clean the gas system with 28ga, .357, and .17/22 brushes. The 28ga for the gas cylinder, the .357 for the plug and the .17/22 for the piston. With a good cleaner, I use wipe out, it gets everything out. For the ports we use pipe cleaner. Is this wrong or just not as effective?

Thanks in advance.
Good question I was wondering this also, seems like bits would be for some serious buildup.
 

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Discussion Starter · #16 ·
If it works, it works. The drill bits make short work of thick buildup but if a brush and solvent does the job, go for it. I use the brushes after the drill bits for the fine cleaning.
 

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Tonyben, thanks for the feedback. Maybe one day when I have the time and money to throw more lead down range I'll get the drill bits. HAGO.
 

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We always used the drill bits we could get through the Federal Supply System, so the angle of the point was not specially selected for possibly doing less cutting damage. As long as you turn the drill bits by hand, you are not going to dig/cut into the metal too much.

"Back in the day" when M14's were issued as the standard Infantry Rifle, one cleaned the large hole n the piston with bore solvent and a bore brush. Many folks never realized there even WAS a smaller diameter hole that went back into the tail of the piston. Even at the 3rd Echelon Infantry Weapons Repair Shop, we did not have the drill bits. I first learned of them when I was going through my OJT to become an RTE Repairman.

The large hole is difficult to clean properly with a brush, but the smaller rear hole is even more difficult to downright frustratingly hard without the drill bits.

The guys at Rock Island who build the EBR's issue a really great combo tool with them that has the drill bits right on the tool. I really wish we had something like those tools back when the M14 was the standard infantry rifle.
 

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I got my aircraft length #15 drill bits this afternoon, less than 24 hours after I ordered them; got two, a wear and a spare.
I'm having trouble doing a search for these drill bits. Can anyone provide a link to the actual bits on a site such as MSC Industrial Supply?
 
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