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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 ()
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Product Reviews

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  1. 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.

  2. 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.

  3. 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.

  4. Will work on a BM59 with a custom spacer 5 Star Review

    Posted by on 23rd Aug 2019

    Works great on the BM59 if you make a spacer. The dimensions are: 16.51mm outer, inner 14.22mm and thickness of 3.1m. No more torn brass rims.

  5. NOT WORTH IT 1 Star Review

    Posted by on 23rd Aug 2019

    No improvement over the original.

  6. Answer to a Prayer? 5 Star Review

    Posted by on 15th Jun 2019

    I just received my adjustable gas plug and installed it on my M-1Garand. I haven't had the time to take it to the range, but I look forward to dialing it in. As for fit and finish, Schuster MFG takes second to no one.

    I look forward to doing more business with this company and recommend you do the same.

  7. Quick to install and tune. 5 Star Review

    Posted by on 11th Apr 2019

    I bought these after watching the InRangeTv video where Ian and Karl discuss this product and its benefits. After installing it in my M1, 3 quarter turns were all that was needed to bring the rifle to shooting beautifully. I just need to scuff them up to match the rifle's looks.

  8. Adjustable vs High Volume Plugs - Adjustable all the way 5 Star Review

    Posted by on 29th Aug 2018

    After purchasing this plug for my Garand, I had several friends ask about it, I ended up buying several for them and my kids. I did try the "high volume" plugs on two of my kids garands they didn't work (failed to cycle). I found the adjustable plug is the only way to go if your shooting modern ammo (factory or handloads). I've used these in 30.06 and 308 rifles - works beautifully - highly recommended. (the "GI" gas plug tool does on work with these plugs).

  9. Does the job 5 Star Review

    Posted by on 12th Oct 2016

    I purchased this plug to give myself the capacity to tune my M1 Garand. This plug allows me to reduce the recoil for my wife, turn the firearm into a single-shot by opening the set screw for training new shooters, and shoot modern ammo safely. It does that job as advertised, looks good, and feels well designed. End of story.

  10. looks exactly like the original 5 Star Review

    Posted by on 1st Jan 2016

    Perfect fit and look, I have yet to test it out though. The package came wrapped well with a personalized hand written message and a handful of Christmas mints. Thoughtful details that speak to the caliber of company.

0.30 LBS


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