M1 Garand

[Johnw...ski]

Any one know anything about the gas cylinder plugs on the M1 Garand?

I know the old style was solid verses the new which has a spring loaded valve.
It seems to me the pressure in the gas cylinder would keep the valve closed so I don't see the benefit. I have read the solid plugs will give better groups.

My rifle is an early model, SN 255XXX with the newer plug, I also have a solid plug I am thinking of trying.

Does anyone have any experience with this? What are the positives and negatives?

John

[Jack Stanley]

John ,
The valve on the newer one is meant to vent some of the pressure when launching grenades . When the launcher is attached it opens the valve the correct amount for using grenade launching blanks which are indeed different that salute blanks .
For use with Ball ammo the solid plug will work just fine . In the time I've been fooling with Garands , I've seen just one vale that was cracked but it didn't seem to affect the performance of the rifle . Could it leak ? well yeah , the more the valve is opened the more chances there are to get debris in it and cause it to leak . Could it break ? yep , it has more parts than the solid . Is it a big thing to fret about ? no , but it does give you a mission to take the rifle out and fire it to see which you like best

Jack

[Johnw...ski]

Thanks for the answer Jack, that makes perfect sense, but that brings up the question, why do they make adjustable plugs?

John

John ,
The valve on the newer one is meant to vent some of the pressure when launching grenades . When the launcher is attached it opens the valve the correct amount for using grenade launching blanks which are indeed different that salute blanks .
For use with Ball ammo the solid plug will work just fine . In the time I've been fooling with Garands , I've seen just one vale that was cracked but it didn't seem to affect the performance of the rifle . Could it leak ? well yeah , the more the valve is opened the more chances there are to get debris in it and cause it to leak . Could it break ? yep , it has more parts than the solid . Is it a big thing to fret about ? no , but it does give you a mission to take the rifle out and fire it to see which you like best

Jack

[NuJudge]

The new adjustable plugs are made so one can use powders that are slower than what the Garand was designed for, venting excess cylinder pressure, and preventing bending of the Operating Rod. The Garand was designed around 3031-4895-4064 speed powders. Rifles such as the FAL have adjustable gas systems, but the Garand does not.

The original Garand solid plugs never go bad.

The popet valve ones made late in WWII for use with grenade launchers and continuing through the end of production do go bad eventually, venting when they are not supposed to.

[dominicfortune00]

As I understand it, the adjustable ones are for people who want to try different powders(slower or faster than IMR 4895) in reloaded ammo in a Garand.

Reloaded ammo with too big of a pressure wave peak can bend the op rod.

The adjustable is set, or can be set so that it cycles the action using M2 ball ammo, any pressure over the M2 levels would be vented to prevent damaging the rifle.


Unless you're going to try to work up a load using different powders or bullet weights, you probably don't need one.

[Jack Stanley]

In addition to letting you use slower powders , the vented plugs allow you to try heavier bullets . If I remember right the military had a 173 grain FMJBT , with a vented plug you might be able to use hundred and ninety grain match bullets very effectively .

Jack

[smokemjoe]

I pushed the plug out on one of mine, now shoot 17 Grs. 4759 and 200gr. bullets, run the bolt by hand, no leading in the barrel port, better groups,got a single shot mag. block and no more M1 thumbs, Had 3 smashes in 2 weeks, got a B square scope mt. on it. Works great. Joe

[NickSS]

One thing about the adjustable plug is that you can tune them so that the empties just fall in a nice pile. I usually use 4895 or 4064 and 168 gr HPBT match bullets. Before I put an adjustable plug in the brass went frontwards and to the rear. So I had to hunt a considerable area to pick it up. I put in a Shuster adjustable plug and slowly closed the gas bleed hole until the brass was reliably ejecting and it is all landing about two feet to the right rear os where I am shooting from. Makes a pile about two feet in diameter. Also softens the recoil and lowers wear and tear on the oprod.

[Johnw...ski]

So as I understand it the solid plug may help grouping. Does this mean that with an adjustable plug there is a trade off with accuracy?

So far this year I have shot almost 1000 rounds of 173 gr. FMJBT bullets with
60.0 gr. of H4831SC using the issue spring loaded gas plug with no ill effects other than the op-rod spring seemed to have gotten tired but all was well after I stretched it 1-1/2 inches.

This load has been extreamly accurate out of my rifle and I am wondering if the solid plug would help.

When this lot of bullets runs out shortly I plan to use the Hornady 150 gr. FMFBT with about 58.0 gr. of H4831SC. I am still working on the final load for this bullet and am close accuracy wise to the 173 gr. bullet at 200 yds. so far.

[bruce drake]

Nope, The adjustable gas plugs (mine is a Schuster) allow you to use slower powders or heavier bullets. It also allows me to tweak the load where I can dial the load into the rifle. I've seen noticeable improvements in the accuracy of my Garand with a given load. It's another variable for the handloader to deal with besides bullet weights and powder charges.

If you want to focus on one less thing, than go with the older plug. The schuster plug is different than the older valved plug which as they mentioned correctly before was designed to shoot blank charges of very fast powders to launch grenades.

[tejano]

I pushed the plug out on one of mine, now shoot 17 Grs. 4759 and 200gr. bullets, run the bolt by hand, no leading in the barrel port, better groups,got a single shot mag. block and no more M1 thumbs, Had 3 smashes in 2 weeks, got a B square scope mt. on it. Works great. Joe

I have had a Garand for several years, but I have not shot it as much as I do my other weapons. However, I did come real close to getting an M1 thumb the first time I took it to the range. I am left handed, but have always shot rifles right-handed. I load with my stronger left hand and keep my right hand on the operating rod handle just in case. Yeah, I know that is not the way I have seen it done in movies, but it seems to work. Or, is it just heresy?

[Jack Stanley]

Being left-handed myself , you would think my thumb is half gone form the problems folks blame on the Garand bolt . While I'm feeding mine , I've noticed that the bolt cannot come forward untill your thumb lets go of the ammo . So , I'll hold it down completely untill I'm ready to get the thumb out of the way ..... and then , do that quickly .

Jack

[PatMarlin]

Never hear of the garand thumb. Could you explain that some more?

I bought mine earlier this year and have not fired it yet..

[NickSS]

M1 thumb comes from incorrectly inserting a loaded clip. The right way is to set it in the rifle in position. Put your thumb about midway down the length of the cartridges and push it into the rifle smartly until it stops at the bottom. Then in one fast motion pull your thumb and hand away from the action. The bolt will release and slam forward chambering the first round 9you may have to bumb the op rod handle to get it going. The wrong way is to do the same thing but then be tentative about geting your hand out of the way. This will result in the bolt slamming shut with your thumb still in the action. The resulting mangled thumb is known as M1 thumb. If you are unsure you can place your fingers of your right hand alongside the action and hold the oprod to the rear while seating the clip. That way your fingers will block the oprod from closing until your thumb is out of the way. When loaded properly there is no problems and you can get of at least four clips in one minute of aimed fire. My own record is 38 rounds in a minute.

[45 2.1]

You get M1 thumb only once (or at least you should). If you get it twice, you will probably sell the rifle. Takes a long time to heal also. BTDT while trying it right handed. I'm left-handed though and developed my own method of rechargeing. Roll the rifle to the left, insert clip with left hand and push home while pad of left hand is on right side of rifle blocking the operating rod handle. Once it locks withdraw fingers, then hand and let slam shut. No mangling that way.

[waksupi]

If you want an advanced course in sore thumbs, get yourself a Hakim, and not pay attention when loading. Those are like blunt guillotines, travelling at 1100 fps.

[B747]

Also, keep in mind that the Garand has a floating firing pin that will at the very least make an indent mark on the primer if you release the bolt from all the way back.

I've had a slam-fire on mine even with a CCI #34 military style primer with the hard shell is supposed to help prevent that. When single round loading I now drop the bolt from about half way closed to keep bolt closing speed down.

A slam fire is always a bad deal --- if it occurs out of breach lock, really bad things will happen.

Wally

[PatMarlin]

All right... thanks!

[garandsrus]

My belief is that M-1 thumb normally comes from not having the bolt locked all the way to the rear, while thinking that it is.

The bolt will remain open when it is behind the follower, but it is in fact not "locked". It can come loose very easily, slamming shut. The bolt "locks" about another 1/4 to 1/2" to the rear.

A "Single Load Enhancement Device" or SLED is a great way to load the Garand single shot and worth way more than the $10 or $15 they cost. You put the SLED (which is a modified enblock clip) into the rifle and it stays put until you remove it, which is also very easy. Then, you just snap a round in the clip. When you are ready to shoot, just pull the op rod back and let it go. The round will chamber. This is especially useful for left handed shooters when using coats, shooting gloves, slings, etc.

The SLED does load the round from a clip, so the op rod is going the proper speed.

John

[sundog]

I am a southpaw and I love the Garand. The SLED is essential for me for high power as far as I'm concerned.