Ported Gas Plug (TM)


The Ported Gas Plug™ has an open area in the base of the screw that increases the starting volume of the gas cylinder. This causes the peak gas pressures in the gas cylinder to drop by over 30%.

(29 customer reviews)


Notice:  The CMP has recently updated their recommendation for ammunition use in their Military Surplus rifles.  Please see their notice at the link below.

[CMP Service Bulletin for the M1, 1903,1903A3]

Please note that the Ported Gas Plug™ for the M1 Garand ONLY deals with pressures in the gas cylinder and is not a device intended to lower chamber pressures of the rifle.  Please follow any recommendations set forth by the CMP and verify the headspace on your rifle is also in spec.

Our custom gas screw has been designed to help you safely shoot commercial ammunition hassle free in your M1 Garand. Our gas screw has a open area in the base of the screw that delays the operating rod for several microseconds and lowers the peak gas cylinder pressure by over 30%! Unlike a vented gas screw, ours requires no adjustments and is ready to use right away. The Ported Gas Plug™ can be installed using a standard 1/4 socket driver! Our gas screw does NOT vent gas like a vented type gas screw. The secret is the open area in the base of the screw which increases the initial volume of the gas cylinder. By increasing the volume, the peak pressures are reduced without the need to vent the gas.

Customer QuestionsQ: Will the Ported Gas Plug™ work with normal M2 Ball Ammunition? A: Absolutely! The Ported Gas Plug™ will work with all M2 ball ammunition types made. The gas system on your rifle should be in spec and not worn out.
Q: Will the Ported Gas Plug™ work with low pressure loads? A: This is a harder question to answer without knowing the load being used. If there is enough gas pressure to cycle the rifle with a normal gas screw, then the Ported Gas Plug™ should operate correctly. If the load being tested is marginal, the rifle may not cycle reliably.
Q: The product mentions the potential for increased accuracy. Can you explain that? A: Accuracy in it’s most basic form is the ability of the rifle to remain unchanged from shot to shot. The M1 has several factors inherent in its design that can cause the rifle to move or shift slightly from shot to shot. Forces acting on the barrel can change between shots. If this occurs then the accuracy potential is degraded. The Ported Gas Plug™ does two things. The first is to delay motion of the op-rod for a few microseconds. (delays the forces applied to gas piston). This helps keep the system more static until the bullet has left the barrel. The second is to reduce how hard the op-rod is forced rearward. This reduces the natural flexing and bending the operating rod experiences and helps the rifle return to the same state between shots. Recall that accuracy potential is a result of the sum of all the factors acting on the rifle. The Ported Gas Plug™ will not make a 5 MOA rifle a 1 MOA rifle.
Q: Will the Ported Gas Plug™ work with a gas system that is worn out? A: The gas screw is designed to work with an M1 Rifle that has a gas system that is in spec. That is to say, not worn beyond the normal reject levels. That would be a gas piston with a diameter between 0.5250″ and 0.5260″ and a gas cylinder that is between 0.5280″ and 0.5320″. The operating rod spring should also be in spec and not worn excessively and the rifle properly greased.
Q: Can I use the Ported Gas Plug™ on a Tanker or a M1 Garand with a short barrel? A: The Ported Gas Plug™ is designed to work with a standard length M1 Garand Rifle. A Tanker or short barreled M1 moves the gas port closer to the chamber and results in gas pressures that are many times higher then a M1 Garand was ever designed to operate with. The Ported Gas Plug™ is not suitable for use in this application.
Q: Can I use a bayonet with this gas screw? A: The Ported Gas Plug™ is NOT designed to accept a bayonet with a lug that inserts into the gas screw. The lugs on the bayonet are larger in diameter then the 1/4″ cutout on the gas screw and will not allow the bayonet to be fully seated.
Q: What causes an Op-Rod to get bent? A: There are three factors that can result in damage to the Op-Rod. The first is high pressure in the gas cylinder. The second is binding of the Op-Rod, and the third is poor lubrication. If any two of the these three conditions is present then damage is possible. If the op-rod is binding then the operating rod will flex and bend when cycling until the bind is overcome. This causes the operating rod to flex and damage is possible. Our Ported Gas Plug™ reduces the peak pressures in the gas cylinder, which in turn reduces the peak forces acting on the operating rod. Always check your M1 for binding by performing the [Tilt Test].

The effect of the Ported Gas Plug™ design is shown below. 

Gas Pressure Data

        (Click image for full view)     Custom Made in the USA

[Installation Instructions]


Weight 0.1 lbs
Dimensions 1 × 1 × .75 in
Country of Manufacture

  1. Trevor

    6 Years, Going Strong

    I bought my ported Gas Plug 6 years ago. I was trying to figure out a way to use more commercial ammo, without worrying about bending my op-rod. I was looking at adjustable gas plugs when I came across this one. I watched the video and looked at the extensive research done with a lot of different ammo and I was convinced that this was the way to go for me. I knew that I was going to do mostly plinking with my M1, which means I was also going to be buying some of the cheaper ammo out there. I didnt want to worry about bending my Op-Rod because I put something other than GI loaded ammo in the gun. I will say that in 6 years I have never had a problem, and trust me I am crazy about checking the wear on my gun.

    If you are looking for peace of mind when it comes to undue stress on your M1 then this is hands down the gas plug for you.

  2. Richard

    Why not

    I ordered 2 of these to protect the operating system on both my M1’s. just shot a match last weekend with one of mine. and worked flawless. I liked the concept better than getting an adjustable plug for them.

  3. Gregg


    Year #2 still not a hiccup the only issue is you recommend to tighten it to tight. I told a friend who purchased one. Any made it way to tight.. Any way we fixed it in my shop. I ordered another rifle when I get it I will order another. Thanks.

  4. Josh

    functions flawlessly

    Bought this to run Remington core-lokt. Functioned exactly ad advertised, zero malfunctions. I would very much recommend it. The only thing that would make it better would be if it were compatible with the M3A1 combination tool.

  5. Infantry327

    Great product

    I installed the new gas plug the day before shooting and was using Remington 150gr core lok and my M1 performed flawlessly. After much research and reading it was not a hard decision to give my rifle a little extra protection and flexibility in ammo use.

  6. Patrick

    Ported Gas Plug

    Bought two ported gas plugs. One for regular Garand 30-06 and one for my tanker .308.
    Both work great. I was having a problem with the tanker ejecting the spent rounds into my shoulder. Changed op spring and hammer spring with no difference. Bought and installed
    The ported gas plug and it now ejects at About three o’clock. For me, it works in a tanker.

  7. Ozzy

    Worked great in my .308 Garand.

    Worked like a charm in my .308 (7.62×51) NM Garand. Tightened up my groupings at 200 yd using PPU FMJ BT 145gr 7.62×51 M80 ammo. Can’t wait to try it in a match and with other ammo.

  8. Gregg

    Great idea great product

    Had mine over a year now. Great product . I’ve had my rifle more than 25 year’s now when they were not so popular. But I always kept it clean and well greased. I used to buy bag’s of 100 surplus round’s for $20.00 good old days. Was in the service 28 years so i
    didn’t do much recreational shooting after 9/11 we were busy retired in 2008. Got back into shooting and got this computer and learned about certain ammo found this plug and nu worries. I still try to stay within the boundaries. But it’s good to know I can shoot reloads to modern ammo with out issues well worth the money

  9. David

    so far so good

    So i’ve tried twice now to share my videos on here of my trials using this, so far, amazing product. I am a “youtuber” or at least trying to be one. I have attempted to put on video my ammo testing with this product. As my summary says: so far, so good. I haven’t noticed any damage on my rifle so far and it seems to function fine. For any that are curious my youtube page name is Gunlover82. Search for the ammo testing. So far this is a great product and appears to work as advertised. Buy one and try for yourself!

  10. KERRY

    Hot Loads Eject to the Side or Front Now

    After reviewing the excellently presented research offered on this site (I know enough physics to be wary), pontificating and just being skeptical….oh, and reading these reviews…I purchased one.

    I was motivated by my stash of HV ammo that I had for my 1917 Eddystone, and was repelled at the prices for Garand-specific ammo.

    After a day at the range shooting a hodgepodge of Remington, Winchester and Fiocchi hunting cartridges (up to 3Kfps MV), I am SO pleased.

    The casings ejected to my side (two feet) or in front of my station. I also experienced a lesser recoil. I am a skinny kid of 64 years old, so it is good.

    I shot well for an old guy at 100yds (6″ group of three, five inches above the bulls eye). Then I had to go. Da!M women.

    Great product. Arrived early. Cannot say how much this site and product helped me!

  11. Chris

    Must have!

    I am an engineer, and wondered about the effectiveness of this item. Three things have confirmed it:

    1) I had to bump up the charge 0.2 g (of H4895) in my handloads to get the gun to consistently cycle, indicating less pressure on the op rod than with the vintage plug. Now, the bolt cycles back just far enough to consistently catch the next round and ping the clip. Perfect! Felt recoil is more of a push than a pop.

    2) Better yet (as I believe someone else has said), before, my brass was beside me, in front of me, and behind me. Now, it is consistently behind me in a 4′ radius. This make it much easier to find brass.

    3) Gun (’44 SA) was grouping about 2″ at 50 yds. Now, I am shooting – no lie – about 3/4″ at 50 yds. Why? I think it is because the shot cycle is much more consistent, and I settle back into the next shot more easily.

    This is well worth the money.

  12. Will

    No-brainer…just get one

    I bought a ’43 SA Garand a couple years ago with a new criterion barrel and match stock; what a weapon. There is something about the marriage of parkerized steel and dark wood that gets me. She can easily pop melons at 100 yards, and is a great conversation piece to boot. Being an obsessive internet researcher, I learned that advances in powder technology have allowed for a lot more bang to be packed in the substantial 30-06 case than was possible back in WWII. If you are content only shooting surplus ball ammo and you have an infinite, cheap supply, then this plug is a waste of 45 bucks, the USGI one will work fine. If you are like most M1 owners, you want to be able to go to any sporting goods store on a whim and pick up a box of commercial ammo to shoot. I don’t know about you guys, but I did not feel comfortable shooting commercial ammo with my GI plug fixed. After running through a stash of M2 ball I bought at a show, I came upon the Garand Gear gas plug as a solution to my ammo woes. Compared with an adjustable plug the Garand Gear Ported Plug seemed too good to be true. How could it allow the weapon to cycle with 150 grain surplus ammo and hot Hornady Superformace loads that have 20% more muzzle energy(3178 vs 2655 lbf)? Then I read the description which explained the science behind the ported plug, and I saw the light. Hats off to Garand Gear for the graphs and data, I do not think I would have bought this product otherwise. Thorough product testing is so valuable I can’t even imagine how many operating rods they mangled for our benefit to get those control numbers. What sealed the deal were the positive customer reviews on this site. Shipping was fast and installation is as simple as unscrewing the old plug and screwing the new one in place. I have had the Ported Gas Plug for a little over a year now, and the M1 has happily eaten every type of ammo I have fed it, with no cycling issues concerning enough that I can remember. The menu included a healthy diet of 180g Remington Core-Lokt soft points along with various other loads. The most important factor is that it turns any M1 into a fun, carefree shooter. These guns are pieces of history as well as beautifully crafted machines, and they are meant to be enjoyed. Being able to throw any ammo into the clips and plink has allowed me to enjoy my Garand more thoroughly. For example I was able to shoot a box of hot commercial ammo that my buddy gave me at some pumpkins. Overall, I am extremely grateful that Garand Gear invented this thing because it allows Garand owners to shoot more, period. BUY THIS!

  13. Shane

    No More Worries With Commercial Ammo

    This product is an absolute must-have for any M1 Garand. I ordered it shortly after I purchased a 1942 Winchester at a local gun shop last December. I’ve shot over 500 rounds with various bullet weights from various manufacturers and the rifle has functioned flawlessly with no damage to the op-rod. I don’t plan on ever using the stock gas plug.

  14. Bradley

    Works perfectly

    This seems to work as advertised. It has worked flawlessly on my CMP “service” grade rifle. Replaces the original exactly, and you can only tell by very close examination. The only difference is the cross in the screw is slightly more shallow. Fit and finish otherwise is the same as the original screw. I have an original modified (cut down older longer model) WWII bayonet, M1905E1 style, and it fits perfectly with this screw in place. The M1 and earlier bayonets have a ring that goes around the muzzle, and fit over this gas screw perfectly. The later M5 style bayonets have a small knob that fits down into the cross of the gas screw, instead of going around the muzzle. Those might have issues with this gas screw since the cavity made by the cross is more shallow. Others have suggested some light grinding of the knob with a Dremel and re-blacking the grind marks will make them fit, but since I don’t have one, I can’t confirm.

    I can tell this screw reduces the stress on the op-rod and all the parts in the action. My rifle used to throw most of the brass over my shoulder, waaaay behind me, before installing this screw, even with surplus rounds made specifically for the Garand. Now, almost every round comes out relatively gently, and only a few feet straight to my right, or even slightly in front of me. It is also a lot more consistent as to where it throws the brass. This screw makes the action work more gently and consistently.

    I’m on here right now ordering another screw for my new CMP “special” grade rifle. The special is an almost new Garand, starting with a receiver in good shape, reparkerized, and mated to a brand new Criterion barrel, a new stock, and finished off with “like new” refinished old parts and new parts. I plan on shooting this one more than my WWII vintage rifle. I may even do things I wouldn’t dream of doing with my old one, like replacing the upper hand guard with a rail, for modern optics.

  15. AFJuvat

    Valuable addition to your Garand.

    Easy installation. Lets you shoot a wider range of ammo in your Garand without beating up your op-rod.

  16. Frank

    Great Product for Garand Shooters. “Ported Gas Plug”

    This product exceeds its expectations. Now I can use commercial ammo. Lots of hard work & time must have gone into the development of this product and the data doesn’t lie.
    Thanks from all of the recreational shooters who benefit from this product.

    Frank Picini/New Grand owner

  17. Kevin

    Garand + Commercial Ammo = Shooting Nirvana

    If you have never fired quality modern commercial ammo out of your M1 you do not realize what you are missing. With the Garand Gear ported gas plug I will no longer waste my time on surplus ammo.
    Shooting Remington and Federal 150gr, 250 yard hits on steel were a given. Out to 500 yards I struggled a bit with my eyeglass vision but my buddy was easily hitting the targets. Easily outshot a modern .308 shooting new NATO spec ammo.
    Modern ammo with modern grease and modern cleaning supplies will make this M1 a regular at the range from now on.

  18. Timothy

    The best product and customer service

    First the product
    This product makes my m1 into a practical and useful tool or hunting and defense. I was in fear that I could find any m2 ball ammo out there ( I did eventually) but this product solves that problem and If I need ammo I can get it anywhere.
    Now the customer service
    Only one other person in my life has given me the quality service I have seen here, my own hometown gun shop. Eric has the best service I have ever seen on or near the web keep it up man.

  19. Tyler Hagen

    Just got mine to the range yesterday, shooting a mix of Remington 150gr soft points and American Eagle M2 Ball-spec; it performed flawlessly. For those of you worried about the bayonet, one of the M1 bayonets should work fine for most applications.

  20. Oscar Andrew

    thank you, i feel safer shooting my 180gr big game loads without any worries hurting and/or damaging my garand

  21. David Boyd

    Great product. Attaching bayonet is simple. Remove micarta handles, use a Drexel tool to remove a minuscule amount around the bayonet lug. Takes less than 10 minutes. Works perfectly. Touch up with flat gun black if it suits your fancy.

  22. Nathan Huckins

    I have bought several of these and wouldn’t shoot without one. It fits great, locks in tight, and just flat out works. I’ve fired thousands of rounds through many rifles with these on them and they 100% work. Nate H Midland, MI

  23. Terry Larson

    Love my ported gas plug. Only complaint is that the plug will not accept the M5A1 Bayonet. The pin on the bayonet will not go into the tightening port on the gas plug.

  24. Kevin Stepherson

    For those of you concerned. I bought this gas plug for my Garand, installed it on my already gauged gas cylinder with the go/no go gauges provided on this site I then took it to the range and sent about 60 or so .30-06 150 grain down the range with no problems at all. I am really satisfied with this product.

  25. Jerry Medlock

    I didn’t buy my CMP Garand to hang over the mantel, but to shoot. Am well pleased with the rifle, and couldn’t wait until the Ported plug was once in stock. Just ordered one.Thanks in advance.

  26. Michael Shelton

    Fit like a charm. Eric has done a great service to the Garand community with his research and great product. I feel better having it than not. Mike S.

  27. Bradley Duncan

    Only time will tell if this plug does all it is claimed to do, but the research that has gone into it is highly regarded over at the CMP Forums. If it does indeed protect our M1’s it might be (dare I say it) the best improvement in the M1 since the original design. I hate tuning my gas venting plug when changing loads and surplus ammo is getting hard to find and expensive. This plug could be a game changer, allowing future generations to enjoy M1’s, hassle free, just as us old guys have done.

  28. Michael Jones

    Great fit and finish. Easy install. Can’t wait to put some modern hunting loads through it. Goodbye piggies.

  29. Louis Lovett

    Although I just recieved and installed on my SA Garand , and test fired 3 different ammos ,it seems to work as advertised, will add to review as i have an opportunity to run some different loads through it.

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