M1 Garand ?

ken792 · Sep 28, 2014

You have adjustable plugs like the Schuster, which vent gas out to reduce pressure. You must adjust the screw to tune it to specific types of ammo. There is also the ported plug from Garand Gear, which is simply hollow on the inside. By being hollow, it increases the volume available for gas to expand, so it reduces the pressure.

The GI gas plug comes in single slot and + shaped (to simplify things). The + shaped gas plug has a poppet valve, which is meant for the M7 grenade launcher. The grenade launcher pushes the poppet in and vents all the gas out, so the action will not cycle when firing rifle grenades. Neither are adjustable gas plugs.

http://www.garandgear.com/m1-garand-ammunition

Some commercial ammo peak pressure is within what military ball is, but the ported plug reduces peak pressure while still allowing the gun to cycle.

Ponder_MD · Jan 15, 2021

fred333 said:
This's what I'm using:

(click pic for link)

This ported gas plug does not appear to be adjustable and I would only trust it with a grain and pressure within a certain range. I would not trust it with "any" 30-06 commercial ammo.

May I ask what brand/spec commercial ammo you're using with this plug?
-----------------------------

The Schuster plug is infinitely adjustable and has fewer "fiddly bits." The downside is that when it starts fouling after 40+ rounds, you have to remove it, pull the set screw out and clean it. There are opportunities for dropped/lost setscrews and whatnot.

I've also seen a "kit" of 5 different plugs. You step down until you find the plug that cycles the rifle effectively. When it fouls, you simply ream it with a small bit or pipe cleaner. Less chance of losing something *if* you stick with a single kind of cartridge. The downside is that there are more fiddly bits. You have to swap plugs around a lot unless you stick within a narrow range of pressures and weights.

With the current scarcity of ammunition, The Schuster plug might be the better way to go because you might change ammunition types frequently as you buy whatever is available at any given moment.

When ammunition is plentiful and you can stock up on a single type, the 5-plug kit might be more convenient because you can stick with a single plug.

I'll probably end up buying both types.

midnightSGT · Jan 16, 2021

well by the pictures it looks like it came home with you! Congratulations.

spoon059 · Jan 16, 2021

I use the GI gas plug bought Garand specific 30-06 ammo. Then I bought a reloading press and started to make my own ammo that copies M2 ball ammo. Little IMR 4895 and 150 grain .308 caliber projectiles and I can shoot safe ammo all day long... or as long as my shoulder lasts, whichever comes first.

Doco Overboard · Jan 16, 2021

The first M1 rifle I owned I used whatever I could find to shoot in it and never damaged anything. The read this first that I was able to get a hold of much later indicated the rifle was designed for any government loaded cartridge including M1 ball. That stuff was like 48,000 cup.

Ngrovcam · Jan 17, 2021

A1Uniform said:
My comment referred to 30-06 ammo through an unmodified-vintage M1.

Having seen more than few damaged op rods, I would disagree with the guy in the link that called a myth though.

A1Uniform, I collect Garands, when the
pocket book allows. Occasionally shoot
‘em, as well. And, certainly, I am no
expert or gunsmith.

I do not take issue with your post.

While I prefer military ammo, I’ve not
had problems with commercial ammo.
Of course, why tempt fate?

But, wasn’t there a piece in the last or
next to last issue of the Garand Collector’s
magazine that took issue with the idea that modern ammo bends op rods?

I’ll have to go back and look.
It is a very worthy topic for discussion.

ken792 · Jan 17, 2021

Ngrovcam said:
A1Uniform, I collect Garands, when the
pocket book allows. Occasionally shoot
‘em, as well. And, certainly, I am no
expert or gunsmith.

I do not take issue with your post.

While I prefer military ammo, I’ve not
had problems with commercial ammo.
Of course, why tempt fate?

But, wasn’t there a piece in the last or
next to last issue of the Garand Collector’s
magazine that took issue with the idea that modern ammo bends op rods?

I’ll have to go back and look.
It is a very worthy topic for discussion.

Yes. Bolt velocity is slightly higher, but not unreasonably so

https://thegca.org/wp-content/uploads/2020/07/M2-Ball-Facts-vs-Myth.pdf

Doco Overboard · Jan 17, 2021

There was also response by Gus Fisher with other experts in the following journal that providing additional info for additional points of consideration based on range experiments and specialty ammo design for the m14 and long range shooting. The comparisons made are based on the round count based on wear characteristics of both the M1 and 14 rifle.
The article shows an op-rod gauge used for a M1 and talks about metal fatigue as a precursor to bending or breakage but does not make a clear distinction between the two rifles or barrel/chamber characteristics that could have been fitted prior to using the king bullet and unknown powder that caused trouble for some shooters.
The last paragraph is interesting in that it indicates off the shelf ammo is available for M1 rifles that can be used vs surplus to meet shooter needs and that other types of commercial ammo may or may not be suitable more than likely from small differences between lots.
Probably good advice when proper maintenance or wear characteristics cannot be determined due to the amount of rifles available to the public and user knowledge of the weapon system remains unknown.

View attachment Ammo-Part-3-article.pdf

Batt816 · Jan 17, 2021

ken792 said:
Yes. Bolt velocity is slightly higher, but not unreasonably so

https://thegca.org/wp-content/uploads/2020/07/M2-Ball-Facts-vs-Myth.pdf

Good article. Thanks for sharing.

Ponder_MD · Jan 17, 2021

midnightSGT said:
well by the pictures it looks like it came home with you! Congratulations.

I tagged onto this thread. The photos are not mine. My rifle is in processing and I don't expect to have it for 8-12 weeks...possibly never, depending on the political climate.

Doco Overboard said:
The first M1 rifle I owned I used whatever I could find to shoot in it and never damaged anything. The read this first that I was able to get a hold of much later indicated the rifle was designed for any government loaded cartridge including M1 ball. That stuff was like 48,000 cup.

This video demonstrates excessive force on the op-rod, which is why I won't fire commercial ammo through it without an adjustable gas plug:

https://www.youtube.com/watch?v=ZQ_F1riBth8

Ponder_MD · Jan 17, 2021

The good news is, in anticipation of my M1's arrival I have scored almost 100 rounds of M2 ball (Greek HXP) and 100 empty brass (also Greek HXP).
I bought 2 boxes of commercial 30-06 that is rated at 2700 fps muzzle velocity but the grain weight is 185 (IIRC), which is outside the spec of M2 ball. For this, I'll use the adjustable gas plug.

I have a friend who reloads his own stuff and he's interested in reloading my brass as an intellectual exercise. I have 100 primers for the 100 empty brass.

IF I actually take possession of my rife, I intend to always keep my brass and reload them so that I eventually no longer have to purchase ammo.

Ngrovcam · Jan 17, 2021

Batt816 said:
Good article. Thanks for sharing.

The Garand Collectors Association (GCA)
is a great organization and the quarterly magazine I’d terrific.

If anyone has even a modest interest in the Garand, the GCA is a must, in my view.

Doco Overboard · Jan 17, 2021

Ponder_MD said:
This video demonstrates excessive force on the op-rod, which is why I won't fire commercial ammo through it without an adjustable gas plug:
https://www.youtube.com/watch?v=ZQ_F1riBth8

I thought they were going to demonstrate a bent or broken op-rod but they didn't. They should have kept shooting until something happened all they got was double.
At 6:55 and 7:15 or so in the video you can see the excess gas blowing past the op rod piston with the different ammo types. Some of the lighter ammo has more gas expulsion vs the ammo with the heavier bullet weight or so it seems. Maybe the heavier ammo made for better powder burning characteristics for whatever type was used hard to say.

I attached pictures of what can happen with a worn op rod spring. The parts are spares I have in my shop. You can see where the op rod was contacting the front of the receiver.

The long angled surface at the left of the rod internal is the bolt open cam. The short angled surface on the right is the bolt closing cam. At the bottom of it is the bolt hold close cam but I cut it off in the picture accidentally. Even with the contact at reciever face these surfaces appear relatively normal with the battering below the hooks.

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