M1 Garand - Gas Plug Question for THR Members

[aspree]

Hello everyone -

I was at the range over the weekend shooting my M1 Garand courtesy of The Garand Guy. The shooter next to me (who told me he owns 2 Garands himself) offered some friendly advice that has raised the following issues.

For reasons I'd rather keep to myself, I wanted to "deactivate" the semi-auto function of my Garand. Therefore, I could shoot one bullet, pull the op-rod back, collect the hot brass, then push the op rod forward to load the next bullet and so forth. If I had my Garand in the semi-auto function, it would shoot the brass back and then some nosy range guy would notice I'm shooting Greek surplus (at a range that doesn't allow bullets that attract a magnet) and then kick me out.

Therefore, I unscrewed the gas plus entirely and set it on my range bag. The gas cylinder lock was still attached to the barrel. After firing my Garand, the gas would completely leave the rifle, the op rod would not push back, and thus the cartridge would not eject. Perfect.

After a while of this, the shooter next to me offered his 2 cents. He said that firing the rifle with the gas plug completely removed would ultimately "injure" the rifle, since the gas plug kept the gas cylinder and the barrel nice and tight. At first I thought, Okay - I can just screw the gas plug into the gas cylinder lock, but not tighten it all the way (Thus, some gas would be retained, but not enough to push the op rod back). But the shooter told me that the gas plug had to be completely screwed in all the way in order to prevent "injury."

Is this correct?

If the shooter next to me is correct, then is it possible to "de-activate" your Garand so that it operates similar to a bolt-action rifle?

(I realize that there are simple alternatives/solutions to my question, namely being (1) don't shoot ammo that is forbidden at your local range, (2) get a brass collector attachment to your Garand, and/or (3) get another rifle. But if you spent a lot of money on a Garand and a lot of money on 768 rounds of Greek surplus, you'd also be pissed when some range guy picked up your brass, asked to see your bullets, and then told you to leave. Of course, there's no one more pissed than me for buying 768 rounds without first finding out the range rules of my local outdoor shooting range...)

 

[41magsnub]

Well.. there are adjustable gas blocks for the garand so you can "tune" it for modern hunting ammo which would be a better choice for this. As I understand it you could adjust the block so it does what you want.

http://www.adcofirearms.com/gasnuts.cfm

When my garand gets here I will be getting one of these since I want to take a deer with it at least once and need to use something other than FMJ for it.

 

[nbkky71]

Well, the gas cylinder lock and gas cylinder plug are both used to keep the gas cylinder in place. Without the plug in place, the gas cylinder should be kept on the rifle by the lock itself. However, the cylinder lock rarely provides a good-tight fit since it has to be backed off a turn (or so) before the plug is screwed into place.

So there may be some truth to what he was saying, although just how much damage would result I don't know.

A better alternative to removing the gas cylinder plug is to use an adjustable, vented gas plug, such as the one made by Shuster. You can adjust the plug to vent the gas pressure and still keep all the gas system parts in place, as they should be.

 

[Gator]

The Schuster nut will work, you could also get an extra gas plug and drill it out. I wouldn't feel comfortable shooting with the plug completely removed.

 

[Mr White]

Exactly what Gator said.

I absolutely would not shoot the gun with the gas plug removed.

In PA, you can't hunt big game with a semiauto. I bought a second gas plug and drilled out the valve. It vents the gas out the front and makes the gun a perfectly PA legal bolt action deer rifle.

 

[Ratzinger_p38]

I cant imagine any good reason why you'd want to disable the semi-auto action, save for hunting with it.

 

[41magsnub]

Here is a stupid question.. doesn't monkeying with the gas block noticeably affect the zero on a garand?

 

[MutinousDoug]

Since the cylinder is no longer being pressurized it will only move from the rifle's recoil. One potential for damage is from the lock coming unscrewed and the cylinder coming off the rifle. That should be pretty easy to monitor and prevent. Another potential for damage might be from the 4-5" lever arm the cylinder itself presents from being attached to the barrel only at the front, so there is potential for a lever type movement about the front mounting ring if the cylinder is not tight on the barrel. If your cylinder is not tight on your barrel, I would think you'd notice it on your target, since your front sight is attached to it. If the cylinder lock is tight against your cylinder, I'd say you are OK. If you have it backed off some angle of a turn, the lock is no longer supporting the cylinder as it would if the plug were installed.

 

[nathan]

I read it will damage the threads on the lock . I in fact just acquired a SChuster Adjustable Gas Plug from Midwayusa as they were on sale.

 

[10X]

As long as the lock is kept in position the gas cylinder won't move, so no damage will occur. Use a small amount of high heat tape where the lock and gas cylinder contact.

An alternative is to use a late model gas plug that has the valve removed. That would better accomplish your goal.

Reading all the restrictions various ranges have, I appreciate the national forest range I use. No cost no rules.

 

[Slamfire]

He said that firing the rifle with the gas plug completely removed would ultimately "injure" the rifle, since the gas plug kept the gas cylinder and the barrel nice and tight.

I would not shoot the rifle without a gas cylinder lock screw holding the gas cylinder and gas cylinder lock together.

Firstly because it is well known that a loose cylinder lock screw will ruin your accuracy. I have had groups move diagonally out to the eight ring in sitting rapid fire. Bullets must have started out in the ten ring and strung themselves out as the plug loosened up. Only determined that the plug was loose after I ruined a perfectly good score.

Secondly, I don’t know what would happen long term to the gas cylinder splines or anything flopping loose at the end of the barrel.

I have taken a perfectly good gas cylinder lock screw, and with a punch, knocked out the gas tappet in the center. I have taken that "vented" gas cylinder lock screw to highpower matches and screwed it in at the long range yard line. I was shooting at a range where brass would eject over a precipice, and I wanted to keep my brass.

The rifle shot to the normal point of aim with a vented gas plug. If the round was hot, it was hard to extract. The Garand does not have much camming leverage for primary extraction. You will find that out, in time.

I recommend greasing your gas cylinder lock screw with Anti Seize. You can get that at WalMart, in tubes, or at Auto Zone.

 

[TexasRifleman]

I cant imagine any good reason why you'd want to disable the semi-auto action, save for hunting with it.

He explained why and I can see a number of reasons depending on the mood of some range officers I've seen.

If you are at a range and your brass is hitting someone else, if you want to make sure your brass is retrieved, if it's muddy out and you don't want your brass falling in the mud.....

There might be lots of reasons to not have the thing throw brass 15 feet away.

 

[jpwilly]

How is the gas plug suppose to be installed? Just screw in and tighten? Mine was loose after my last range session and just discovered this when cleaning.

 

[aspree]

Thank you all for your incredibly helpful input and opinions. I guess the best way would be to buy another gas plug and drill out the center like some of you recommended.

I actually purchased a Schuster adjustible gas plug when I first got the rifle, and have used it when firing commercial ammo. However, even with the Schuster gas plug installed, too much gas was being redirected and causing the op rod to move back and thus eject my brass.

Which begs a new question: Even with a Schuster adjustible gas plug installed, is it possible to let enough gas escape so that the brass doesn't eject? Maybe I messed mine up, but this is the problem - I can screw the actual Schuster gas plug all the way into gas cylinder with my hand and then tighten it completely with my M1 Garand tool. However, when I stick the allen wrench into the plug, it won't let me loosen the nut inside the gas plug. In other words, I can't turn the allen wrench to the left in order to let more gas escape.

My initial conclusion was that the Schuster gas plug was "turned all the way to the left" which meant that the maximum amount of gas could escape the rifle. However, even this setting would still slam the op rod back and eject my brass. Is my Schuster gas plug defective? Or is it impossible to prevent the op rod from sliding all the way back even with a Schuster gas plug?

 

[10X]

aspree, rather than buying an older solid gas plug, you should get one of the newer GI plugs with the valve in it. That is a lot easier to take out than drilling a hole in the solid plug (cringe).

The GI plugs with the spring valve were done for grenade launchers. The launcher had a pin that pushed in the spring valve to allow gas to bleed and not cycle the action when a grenade was launched.

 

[Slamfire]

How is the gas plug suppose to be installed? Just screw in and tighten? Mine was loose after my last range session and just discovered this when cleaning.

What you need are the M10 combination tool and a Gas Cylinder wrench. I stole these pictures from Fulton Armory, http://www.fulton-armory.com/, and that is a good place to start if you want to get them.

The M10 combination tool has a slotted screw driver end that is just perfect for use with the gas cylinder lock screw. If you use the cleaning rod section that comes with the kit, you will not over torque the screw.

Basically, you tighten the thing maybe an eighth of a turn after it bottoms out. Maybe more, all you want is a good firm fit that won't come loose with a lot of slamming and banging.

And that is also why you want to use anti seize. A dry screw will carbonize itself in place. It can be extremely difficult to break them loose once a lot of carbon has built up.

And, always use the wrenchl!

 

[davera]

You can also use the square end of a 1/4 inch socket wrench extension to tighten the plug.

Also, you can open the Schuster valve up enough to make the M1 a straight pull action. The way I tuned mine was to start with it wide open and close it a little at a time until there was just enough gas to eject the round.

 

[Gator]

...when I stick the allen wrench into the plug, it won't let me loosen the nut inside the gas plug.

Somethings wrong there. You should be able to completely remove that screw. It regulates the amount of gas vented by how far it is screwed in or out, you have to be able to move it.

 

[30Cal]

Sounds like the Schuster screw is fouled up with gas. Let it soak in some solvent or kroil and give it a go.

I'd hesitate to shoot the rifle without a plug. It'd be a pain to clean the threads on the gas cyl afterwords.


On the M10 tool, it's a good thing. The fastest way to disassemble a bolt is to chamber the screwdriver end, and close the bolt on it, then rotate the M10 to lift the extractor.

 

[Onmilo]

I think you would be better served by purchasing one of the aftermarket solid gas lock screws and drilling a 3/8" hole through the center to vent the gas.

I understand what the shooter may have been trying to tell you about damaging the rifle should the gas cylinder lock begin to unscrew and the gas cylinder began to move forward under recoil.
You would run the real risk of smacking the gas piston of the operating rod on the ledge of the gas cylinder while manually cycling the action.
This could cause the operating rod to bend and could break the receiver tab off the rod causing the operating rod to dismount from the rifle.

A drilled gas cylinder lock screw will keep everything in place and allow you to use the rifle as a manual repeater.