I'm trying to decide if I should buy an adjustable gas plug for my M1. I live in Kodiak AK and I don't have enough money lying around to get a bulk amount of ammo from CMP. I am slowly getting setup for reloading but in the mean time I'd like to shoot the M1. Is the adj gas plug worth getting? 30-06 ammo is (150-180 grain) is highly prevelent on the island.
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Tim the student
December 31, 2011, 04:28 AM
IMHO, yes. I certainly would get one.
December 31, 2011, 06:19 AM
Most people recommend them for anything heavier than M2 ball. It would make the Garand suitable for 180gr game loads.
December 31, 2011, 08:24 AM
I have an adjustable gas plug and would recommend getting one if your ammo choice are limited.
There are two types available,
The Mc Cann Industries uses a lock screw that comes with several different set screws, each screw tailored to bleed off a specific amount of gas.
The Schuster lock screw has a single set screw that is backed off, then adjusted forward until the rifle just begins to cycle with the ammunition you are using.
If you are looking to tailor to one specific load, I would recommend the Schuster plug, which can be set, then Loc-Tited in place for that single load, the screw won't back out if you do this, causing the gun to malfunction.
The Mc Cann is a better choice if you think you may be using a number of different ammo choices.
The proper set screw for a specific load can be determined and then marked with paint or engraving, identifying it for that specific load.
One thing, I don't recommend using bullets heavier than 168 grains in the M1 Garand, especially using commercial loadings, even with the adjustable plugs.
Some of the heavier loads are very heaqvy loaded and may cause damage to your rifle, even with an adjustable plug in place.
Avoid any commercial loads that are advertised as "light magnum", "Extra Power" or any such indicators the stuff is hot loaded. HTH
I wanted to shoot 190's and IMR 4350 in my match Garand. Thought it would give me a long distance advantage. Not really, my group sizes were worse. If I used the largest gas vent the action would open but not latch. That was OK for prone slow fire. If I used the next largest gas vent the action latched fine, but the action was very violent. With either vent I could tell from the violent slamming and banging that shooting heavy bullets and slow powders were hard on the rifle.
I do believe that with 150's through 175's the gas plug is a good idea you just have to tune the system for reliable function.
The gas plug will radically change your point of impact, I was surprised by how much POI changed after installation.
If you ever reload, the "standard" powder is IMR 4895 and a load that is close to GI spec is a 150 grain 47.5 grains IMR 4895 LC cases, CCI #34.
January 1, 2012, 10:33 PM
A vented gas plug is an excellent idea regardless of who made it. There is a third option which is to make your own and turn your rifle for it. I got a Tanker Garand and the port pressure was out the roof since the port is six inches closer to the chamber.
I have the drawing for the gas plug so I made my own from stainless steel stock and started of drilling it with one of the smallest number drills and shot it and watched the ejection pattern. I opened it up about .003" at a time until the ejection angle was between 1:00 and 2:00 which is the correct angle.
Now I can shoot 150 to 173 gr bullets and all bras will be between 1:00 and 2:00.
I put Mobil 1 synthetic motor oil in mine from the front end and it keeps the carbon soft inside the gas cylinder. I once ran it 150 rounds without cleaning it and the carbon wiped off with a paper towel thanks to the Mobil 1.
January 1, 2012, 10:38 PM
Is the Mobile 1 trick for real ? Sounds good.
January 2, 2012, 12:29 AM
There is a third choice and you don't have to adjust to different loads. I have this on two of my Garands and I have had no problems with them.