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M1 Garand Adjustable Gas Plug


Product Description

By adjusting the volume of gas in the cylinder it changes the speed of the op-rod and controls the harmonic vibration of the barrel.  Our plug softens the blows on your op-rod and wear on the bolt lugs.  Made specifically for use with heavier bullet weights and hotter reloads.  Even if you only shoot your M1 once in a while make it last a second lifetime.   Made from Hardened Tool Steel & Parkerized. Service rifle legal. Same appearance and configuration as the original.  Conforms to CMP 12th Edition Rule 6.1.2.  NOT legal for "as-issued" matches.

 To make installation of your gas plug extra simple use our new M1 Wrench Set.



READ THIS FIRST: Unload firearm before making any adjustments! You will notice that the setscrew in the Gas Plug may be very tight and will not easily turn  by hand. Once installed in the rifle it will become much easier. The setscrew comes at a factory set position, air will easily blow through it. The rifle WILL NOT FUNCTION at this position. Use it as a starting point, then screw in as necessary until rifle begins to function.

Installation:  Remove existing gas plug, and replace with your new adjustable gas plug. Start with setscrew  at the factory preset position. Turning the screw about ¼ turn at a time, tighten screw, and fire until the rifle functions reliably with your particular load. If the adjusting screws seems to loosen, install the hollow locking screw and tighten against the original setscrew locking it in place.  Locating your Rifle’s sweet spot requires some trial and error. Once rifle is functioning properly, try turning the setscrew 1/8 of a turn at a time and fire a few rounds. Repeat until best group is found. Some shooters like to scribe a small line on the setscrew itself, and use it as a marker for identifying plug position (i.e. 3 o clock).

*Since handloading operations are beyond our control, we disclaim all liability for any damages which may result.


 Need a replacement for the locking set screw? Get one here: Replacement Screw for M1 Gas Plug

Product Videos

Making the Schuster Mfg M1 Garand adjustable gas plug 10-3-13 (02:49)
A video of our M1 Adjustable Gas Plug being made on our Haas ST10Y CNC lathe.
  • Making the Sch...
    A video of our M1 Adjustable Gas Plug being made on our Haas ...

Product Reviews

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Showing reviews 1-10 of 17 | Next

  1. T bolt Garand. 5 Star Review

    Posted by on 24th Nov 2020

    The Schuster M1Garand and M1a adjustable gas plugs are awesome. They allow me to develop hand loads for both rifles using non-traditional bullet weights and velocities.

  2. Pressure test 5 Star Review

    Posted by on 28th Sep 2020

    Worked for the .30-06, failed to function the 7.62. Using it to gauge pressure of my reloads vs mil spec 30.06 and 7.62. Neat item.

  3. How to make a new "Tanker" work perfectly! 5 Star Review

    Posted by on 7th Sep 2020

    My "Tanker" modified M-1 Garand in 30-06 was untameable. Jams, tearing off parts of the cartridge by the ejector, I about gave up until I used the adjustable gas plug. Now it's a baby again and I can adjust it for every manufactured ammo I own. I love this thing, why didn't somebody think of this years ago?

  4. Great modification 5 Star Review

    Posted by on 12th Aug 2020

    Installed this on my M1 Garand and found it easy to adjust for optimum performance. Will make the gun more usable with a wider range of ammo.
    Shipped quickly and well manufactured.

  5. Works 5 Star Review

    Posted by on 23rd Jul 2020

    Shipping was extremely fast. It's an adjustable gas plug. Don't know what else to say. Follow the directions. Took about 6 rounds to adjust. Works great.

  6. adjustable high volume plug 5 Star Review

    Posted by on 23rd Jun 2020

    I have not found a place in my area yet to fire the rifle but the quality of manufacture is apparent. I will send another e-mail when I have fired the gun. Thank you for your prompt shipment.

  7. A MUST FOR YOUR M1 GARAND!!! 5 Star Review

    Posted by on 16th Jun 2020

    Guys, if you want to take care of your M1 Garand, the Adjustable Gas Plug is how to do it. It's so easy to set up and it really gives you a peace of mind regarding OpRod speed and damage. For all of you M1 Garand Tanker guys out there, this plug will save your bacon. I just finished with my T-26 Tanker and had it perfectly adjusted in less than 5 rounds, I've ran countless clips through it since and am very pleased.

  8. It works 4 Star Review

    Posted by on 25th May 2020

    It was simple to put in. Only took around 20 rounds to get dialed in. A normal plug wrench does not work on these you have to use a big flat head screwdriver. The only reason I didn't give it 5 stars is because I have never used any of the other plugs so I have nothing to compare it to. But it works good enough for me. So if you buy it you won't be dissapointed.

  9. Quick, Easy, Works 5 Star Review

    Posted by on 21st May 2020

    Only took me one en bloc to get it tuned and I had it running off the shelf gun food without a hitch.

  10. Does What it said 5 Star Review

    Posted by on 18th May 2020

    Take the time to dial this in to use with commercial ammo and you will be happy.

Showing reviews 1-10 of 17 | Next

0.30 LBS


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