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Discussion Starter · #1 ·
Federal Ordnance M14SA (1981?) bought it used in 2013, no idea how many miles (rounds) on her. Had a local smith check headspace and erosion (all good) and I installed gas shims, Sadlak spring guide and new spring. Gas plug is not exactly torqued (I do "that feels pretty tight"). I shoot commercial .308ammo. After a small number of rounds (10-15) I find the plug loose, like 2-3 full turns. Have tightened and shot loose several times now. Saw a TonyB post giving 120-150 inch pounds but I don't have a tool,,,(okay, no tool for this).
Q1 - Will torqueing it to the 120 inch range resolve or is the plug and/or port suspect?
Q2 - Is there a way to back yard estimate for 120-150 inch pounds. Like hand snug and add a 1/2 turn?
Q3 - If I must get a inch pound torque wrench who makes a decent one (not NASA approved).

Thanks in advance
 

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There are a couple reasons that the gas plug could work it's way out; not tight enough to begin with or the plug has a problem.

It's not necessary to use a torque wrench but it's nice to know that it's been tightened to within torque specs. Normally turning it in finger tight and then giving it another 1/8 or 1/4 turn with a wrench is enough. If it still becomes loose then you might have a problem with the plug.

The piston actually strikes the face of the gas plug when it is driven forward by the op rod. If the face of the plug is not flat then this impact tends to loosen the plug. If the plug face isn't flat you can try making it so or simply buy another plug, they're not very expensive.
 

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+1 on what Rammac said! Bottom mine out and around an 8th of a turn is good enough for mine. Shot an Appleseed like this and mine was still good and tight.
 
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From a thread posted by "Gus" Fisher.

2. You really MUST use a Foot Pound Torque Wrench to tighten the Gas Plug when you change the pistons. This is the only way to ensure uniformity for test purposes. The Army used 15 ft lbs. as their torque setting, but we Marines used 23 ft. lbs. as we found in a very few rifles 15 ft. lbs would not keep the gas plugs tight. 23 ft. lbs of torque ALWAYS kept all the gas plugs tight between cleanings. It is kind of funny how we came up with 23 ft. lbs. as the standard. We averaged what four Armorers on THE Marine Corps Rifle Team used individually “by feel” when they tightened up the gas plugs and found it was enough to keep the plugs tight. So it wasn’t from rare mechanical engineering or even scientific analysis, but rather what WORKED.

Some people have tried the test without a torque wrench and by painting or marking a line across the GC lock and Gas Plug to align them each time. Some people actually filed a thin/shallow line across both parts to align them. Either of these things is better than using nothing to uniformly align the Gas Plug each time, but the results will vary much more than when using the Torque Wrench. BTW, if you are a NM shooter or a Long Range shooter, you are only kidding yourself and setting yourself up for A LOT of frustration, if you do not get and use a Torque Wrench.

http://m14forum.com/gus-fisher/109897-m14-gas-pistons-maintenance-their-effects-accuracy.html
 

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Guys was talking about what a competition shooter should do, it's not necessary for the average person.
 

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Discussion Starter · #7 ·
Okay so
TonyB gives 120-150 inch pounds.
(I used an on-line converter for 150 inch pounds to 12.5 foot pounds)
Army is 15 foot pounds.
Marines are 23 foot pounds.
or hand tight plus a 1/8.

I have a pounds torque wrench so I'm G2G once I decided on what setting to try first. Since mine is chicom/FedOrd I'll try 13 foot and see if that holds it.

Thanks to all
 

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I tighten my gas cylinder plug to 15 ft-lbs and have not had one shoot loose at that torque.

If you don't want to use a torque wrench each time, torque the gas plug to 15 ft-lbs, then file a witness mark on the gas plug and gas cylinder lock. All you have to do after that is line up the witness marks.
 

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mine was gorilla tight 1st time i took it out.
so i reinstalled it mid size primate tight.
has not been a problem.
Lruss
 

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I have been using the combo wrench for almost 50 years on mine. I get it snug then just a good tug on the wrench. Never had one come loose on any of my rifles. In Marine Corps boot camp in the mid 60s we were taught to get them " Farmer Tight", what ever that is supposed to mean. I think mine are 1/2 Farmer Tight.
 

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if your looking for an "Okay" torque wrench, goto "Harbor freight" theres are okay for what you would use them for.
 
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I have the very same problem with my Socom16... the gas plug has shot loose a number of times. I'm up to busted blood vessel in my eye tight and that seems to be working.

I have a habit of heavy-handed torque (and the stripped out bolts or sockets as a result) so I am very careful with my Socom... maybe too careful.
 
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Guys was talking about what a competition shooter should do, it's not necessary for the average person.
Maybe so, but one doesn't need it until one needs it.
Two worst places for a gas plug to loosen.............in the middle of a match, and in the middle of combat.
Maybe for us "civilian" shooters, we don't need it that tight, but then our lives and scores don't depend on it. But, I think it would be better to do it, and not have it come loose, than not do it, and have it work loose when one is shooting.
 

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Military spec is to tighten the plug 13 to 17 inch pounds. The Marine's (and the National Guard) have a waver for every rule... Anyway, 180 inch pounds is equal to 14.99 foot pounds of torque. Lubrication will decrease torque, but it depends on what type of lubrication is used. My best suggestion is to replace any plug that won't stay tight when proper torque specs are applied.
 

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We took ours apart every time we shot them. No way was I going to let the armorers find any dirt/crud anywhere in my rifle and give me a ration over it.

We used the GI combo tool to take'em loose and reinstall them and that's all I've used since. Never had it come loose.

Threads (bolt or nut) can be out of spec. due to wear/tear or just made that way.

They make go/no go thread checkers for nuts and bolts. Do they make anything similar to determine if the threads on the gas plug or the gas cylinder are worn/OOS??

If the threads are OOS then they don't get good contact with the other piece (gas plug or gas cylinder) and will work loose much easier. I've seen it on machines at work.

Every try to take a bolt out of an exhaust manifold. Over time, heat up, cool down, repeat/repeat/repeat, the size of the head of the bolt changes (get a little smaller). Any possibility of the threads on a gas plug doing that if the rifle is owned/used by someone who like to burn through magazines?
 
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When I replaced my plug on my loaded the usgi plug felt better and when tight just for some reason is WAY harder to loosen! Maby the sai plug could be your problem, mine never shot loose but came off easier even with antiseze.
 
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