M1 Garand problem

[RetiredUSNChief]

A brother of mine has an M1 Garand, which he asked me a while back to look for some 150 grain ammo for it back when it was harder to find due to all the ammo shortages. I picked up 200 rounds for him and gave them to him when I next visited.

However, he's discovered a problem, and here's a copy of the email he sent to the rest of us brothers:

Just had a school-trained armorer go over my Garand. I'll be replacing my (functional but bent) operating rod in the near future. Long story short, if you want any 30-06 for your rifle, tell me, since I'll be selling off and replacing with specific-to-M-1 Garand ammo.

It seems that 150 grain commercial ammo today develops 62,000 psi chamber pressure, while 150 grain military develops 50,000 psi. The difference leads to bent operating rod, regardless of slug weight (150 gr refers to weight of slug).

So I have a mix of old surplus military and new in FMJ, with some civilian lead-nose to boot...all in 150 gr slug wt. If you want any, then let me know which and I'll set it aside for you. All my civilian ammo is Remington. It's costing me about $120 per 200 rds to buy the American Eagle 30-06 M-1 Garand ammo, so I'll have to jump on it right away to get it at that price.

Available: slightly > 700 rds


In response to my query over the 200 rounds I bought him not being usable, I got this reply:

Looks that way, but you don't find that online anyplace I've looked. The armorer and I have had a couple long talks. The ammo I have is usable, but over time will pound the op rod back out of specs. It'll work in a short firefight, but Got willing that won't ever happen.


SO MY QUESTION:

Are there any Garand owners on the site who have experienced, or read about, this problem?

 

[MistWolf]

I've known about the ammo problem with Garands for decades. You also have to choose powders carefully when reloading

 

[HOOfan_1]

starting load of IMR 4895 seems to be a pretty popular hand load for Garands

 

[TenDriver]

The statement about the op-rod is correct. M2 Ball ammo is perfect for the Garand.

There are a couple of options here.

1. Start reloading. The current factory ammo he has can be broken down, the powder dumped and the rest reused. 46 - 47 gr of IMR-4064 or 4895 is a good place to start.

2. Adjustable gas plug. This allows the gas system to vent off excess gas and keep the op-rod from getting hurt.

If it were me, I'd start handloading for it. My M1 is the reason I started.

As far as Garand friendly ammo sources, it's out there. The best deal is through the CMP for Greek surplus. It's good brass too.

 

[wombat13]

TenDriver mentioned an adjustable gas plug. This is his best option since he already has a large quantity of high-pressure ammo. Much cheaper to spend $36 on an adjustable gas plug than dump hundreds of rounds of ammo.

There are two types, Schuster and McCann. I've got the Schuster for my Garand. The Schuster allows you to start with the gas plug wide open so no pressure is exerted on the op-rod. You turn a screw in slowly reducing the venting over the course of several shots just until the action cycles reliably. Then you screw in a set screw to lock it in place. Now your op-rod is getting just enough pressure to cycle and there is no chance of damage.

The McCann uses several different orifices which you swap out to find the right one. The Schuster allows you to dial in exactly the right amount of pressure while the McCann gets you close enough (a little more pressure on the op-rod than the Schuster) but it is easier to switch between different types of ammo.

 

[TheVision]

There are two types, Schuster and McCann.

There's also a third type, the ported gas plug, by Garand Gear. No adjustments necessary.

The manufacturer has done extensive pressure tests on commonly available .30-06 ammunition. You can see that some of the commercial .30-06 tested falls within LC M2 ball specs, without the need for a replacement gas plug.

 

[morcey2]

Make sure that the armorer knows the difference between the proper bend in a Garand op-rod and an over-pressured bent op-rod. The front section of the op-rod needs a slight bend in it for proper operation. If it was over-gassed and "sproinged", then it needs to be fixed/replaced.



Matt

 

[ArchAngelCD]

Sorry you had to find out the hard way about most commercial 30-06 ammo being bad for the Garand.

In reality it's not the pressure itself that's bad for the op=rod but the pressure curve. slower powders are still building pressure when the gasses hit the gas port. that's what does the damage. I use nothing but H4350 for my 30-05 ammo meant for bolt action rifles but would never use that powder for Garand ammo. Garand ammo is made with 4895 so the pressure curve is correct.

 

[BigBore45]

yes this is true. in the future its best to load your own. i use H-380 powder as it is close to a millitary ball powder. my brother has one as well and it is the only gun he will shoot deer with for some reason.

 

[cfullgraf]

In reality it's not the pressure itself that's bad for the op=rod but the pressure curve. slower powders are still building pressure when the gasses hit the gas port. that's what does the damage.

Right, it is the port pressure that damages the op rod. Current modern powders used in commercial 30-06 ammunition build pressure slower and the pressure at the port is higher when it is open to the gasses.

As said, M1 op rods are not straight, but without the proper equipment and information, it is not something that just anyone can remedy.

I believe the CMP Custom Shop does op rod repairs.

Columbus Machine Works (http://www.columbusmachine.com/oprod.htm) does op rod repairs.

If you have a bunch of commercial ammunition, i would invest in one of the pressure relief plugs. It would be handy to have on hand anyway if you do not reload.

 

[MEHavey]

There's also a third type, the "ported gas plug," by Garand Gear. No adjustments necessary.

Reading the cited reference, there's no "port" to it. It's simply a hollow plug which (apparently)
increases the start volume of the gas chamber/lowering the start pressure. Assuming the test
results/graphs are real, a very "simply elegant" solution (as mathematicians like to say)

The website DID have a really neat Garand Inspection reference though:
http://www.garandgear.com/m1-garand-inspection

 

[RetiredUSNChief]

Thanks! And keep the helpful comments coming. I'll forward this string to my brother.

 

[Reloadron]

Hi Ya Chief, unfortunately you don't mention which commercial ammunition you bought? There is plenty of commercial 150 grain FMJ ammunition out there suited for the M1 Garand from Federal American Eagle and there is also Prvi Partizan Ammunition to name a few. While some ammunition is detrimental other ammunition is just fine for the M1 Garand. So it really depends on what the ammunition was and if it was safe for the M1 Garand.

A popular work around as was mentioned is the use of a Schuster DCM Adjustable Gas Plug as well as similar gas plug devices that allow bleeding off or reducing pressure. These devices make a good work around when good quality ammunition for the M1 Garand isn't available. These come in several flavors as was covered but are well worth looking into.

Since your brother mentions "Just had a school-trained armorer go over my Garand". We can assume the operating rod is likely bent. While as pictured by Morcey2 the "curve" is OK and should be there I seriously doubt a school trained armorer would mistake the normal curve (bend) for the operating rod being bent. Your brother just might want to perform what is called the Tilt Test. Scroll down to #12 in the link. While the merits of this test can be debated it certainly won't hurt to perform the test as outlined. A Google of M1 Garand Tilt Test will also bring up a few videos of how to perform this simple test. Again, can't hurt and will help him become more familiar with his rifle.

Most avid M1 Garand shooters roll their own ammunition and there are plenty of M1 Garand loads out there to be had.

Good Luck Chief....
Ron

 

[USSR]

It seems that 150 grain commercial ammo today develops 62,000 psi chamber pressure, while 150 grain military develops 50,000 psi. The difference leads to bent operating rod, regardless of slug weight (150 gr refers to weight of slug).

Eh, not exactly. The pressure specs for .30-06 is 50k CUP and 60k psi. The perceived pressure difference between commercial and military 150gr ammo is simply not there. How is that? Commercial ammo pressure specs are obtained by using a Piezoelectric sensor by SAAMI, which measures pressure in psi. On the other hand, the army developed their pressure specs using the copper crusher method which SAAMI calls CUP (Copper Units of Pressure), but the army calls psi, which it is not. So, there really is not much difference pressure-wise between USGI .30-06 and MOST commercial 150gr ammo. Where you REALLY run into problems with commercial ammo is when you move up to heavier bullets which tend to use slower burn rate powders. The Garand receiver is extremely strong, and peak pressure is not the problem with it. The weak point of the Garand is it's gas system which was developed around a specific port pressure. The use of heavy bullets with slow burn rate powders raises the port pressure beyond the design specs, and this can result in a bent op rod. Hope this clears things up for some of you.

Don

 

[kwg020]

Ten Driver said:
The statement about the op-rod is correct. M2 Ball ammo is perfect for the Garand.

There are a couple of options here.

1. Start reloading. The current factory ammo he has can be broken down, the powder dumped and the rest reused. 46 - 47 gr of IMR-4064 or 4895 is a good place to start.

2. Adjustable gas plug. This allows the gas system to vent off excess gas and keep the op-rod from getting hurt.

If it were me, I'd start handloading for it. My M1 is the reason I started.

As far as Garand friendly ammo sources, it's out there. The best deal is through the CMP for Greek surplus. It's good brass too.

This.

kwg

 

[Slamfire]

The Garand was type classified in 1936 but it was to be compatible with the 1906 service round. Technology was not as sophisticated as today and the ammunition of the period reflected that. The 1906 round used powders that are not available today and pressures were lower. The velocity of the original 1906 round was just at 2700 fps. As I will address later, it was 2700 fps in a Frankfort Arsenal pressure barrel. Pressures were also low, nothing greater than 50K psia. Based on American Rifleman match ammunition data, there was a lot of ammunition which peak pressures were closer to 40 Kpsia than 50K psia. Might have even been loads that were high 30 Kpsia. What mattered was velocity, port pressure. The breech pressure was a not to exceed. Today’s’ commercial ammunition zips a 150 grain bullet at 2900 fps and I believe pressures are 60 Kpsia.

There are a couple of first order considerations when developing loads for the Garand. The first is port pressure. This rifle is limited by port pressure. If port pressure is too high than the mechanism is over accelerated which will bend operating rods and cause malfunctions.

Pressures too high will cause malfunctions. When Federal loaded ammunition was used at the 2001 Camp Perry Garand Match, it was loaded to commercial specifications. The retired Marine I was scoring, he old enough to be a Korea War vet, his like new Garand malfunctioned with this Federal ammunition. I can recall seeing his partially loaded clip jump up out of the receiver in rapid fire prone, causing a jam, and the Marine looking angrily at it. He pulled the clip out and tossed it on his mat. Since the Garand Match is a no alibi match, the Marine decided to quit for the day and shoot the ammunition at home. There were so many reports of ammunition created malfunctions that the next order of Federal ammunition was significantly reduced in velocity and pressure.

Another concern, beyond bent operating rods, is cracked receiver heels. The bolt rebounds off the receiver heel. Many of these Garands have been fired thousands of times already, so the sidewalls have absorbed a lot of impacts. While rare, Garand and M1a receiver heels do crack.





















This was reported to have been found in a snow bank. No idea of what happened but I suspect it was in low earth orbit before re entry into the earth's atmosphere.

 

[RetiredUSNChief]

Hi Ya Chief, unfortunately you don't mention which commercial ammunition you bought?

A good question. It was Remington, I believe, which is what my brother said compromised all his "civilian ammo".

I don't know about my brother yet, but I'M certainly learning some good stuff here!

All I've gotten from him so far is a short email wanting to know if MistWolf ever read Babel-17. Given what that book was about, I strongly suspect this question came up due to MistWolf's signature quote. (It also means he's had a chance to read through this string today.)

I'll get on the phone with my brother in the next couple days and discuss this stuff with him.

 

[Merle1]

A brother of mine has an M1 Garand, which he asked me a while back to look for some 150 grain ammo for it back when it was harder to find due to all the ammo shortages. I picked up 200 rounds for him and gave them to him when I next visited.

However, he's discovered a problem, and here's a copy of the email he sent to the rest of us brothers:

Just had a school-trained armorer go over my Garand. I'll be replacing my (functional but bent) operating rod in the near future. Long story short, if you want any 30-06 for your rifle, tell me, since I'll be selling off and replacing with specific-to-M-1 Garand ammo.

It seems that 150 grain commercial ammo today develops 62,000 psi chamber pressure, while 150 grain military develops 50,000 psi. The difference leads to bent operating rod, regardless of slug weight (150 gr refers to weight of slug).

So I have a mix of old surplus military and new in FMJ, with some civilian lead-nose to boot...all in 150 gr slug wt. If you want any, then let me know which and I'll set it aside for you. All my civilian ammo is Remington. It's costing me about $120 per 200 rds to buy the American Eagle 30-06 M-1 Garand ammo, so I'll have to jump on it right away to get it at that price.

Available: slightly > 700 rds


In response to my query over the 200 rounds I bought him not being usable, I got this reply:

Looks that way, but you don't find that online anyplace I've looked. The armorer and I have had a couple long talks. The ammo I have is usable, but over time will pound the op rod back out of specs. It'll work in a short firefight, but Got willing that won't ever happen.


SO MY QUESTION:

Are there any Garand owners on the site who have experienced, or read about, this problem?

I still have plenty of MILSURP ammo, so am operating off second hand info. I have been told that an adjustable gas plug will cure this problem.

 

[Mr.Revolverguy]

I love my Garands and each of them have this plug
http://www.garandgear.com/ported-gas-plug.html

It works.

But even with this plug I still load the garand only loads out of the book and I still have 100% functionality.

 

[agtman]

Great thread, great discussion, and the GarandGear links were helpful, but it's prompted two questions for the "gas port" plug experts (whichever model you're using):

First, in my M1s, I'm shooting only standard "mil surplus" 150gn ball ammo, such as the L.C. '52 production that CMP sells, or occasionally, the so-called "Garand-safe" 150gn commercial loads, e.g., Federal or the more recent load from PPU.

For this ammo, is one of these aftermarket plugs even necessary?

Second, some M1 owners have a shorter-barreled "Tanker" model, chambered in either '06 or .308. Some of these have 18" barrels (like mine, which is a 7.62/.308), or 16" barrels - such as the "Mini-G" conversions that Schuff does. He apparently installs a Schuster plug on his Mini-G builds, which, I assume, is to cover a variety of ammo his customers may possibly shoot.

But again, for those guys who have a Tanker, if you're only shooting mil-surplus ball ammo, not the higher-pressure commercial hunting ammo, do you need to use one of these plugs?

Thanks in advance ...

 

[Reloadron]

Great thread, great discussion, and the GarandGear links were helpful, but it's prompted two questions for the "gas port" plug experts (whichever model you're using):

First, in my M1s, I'm shooting only standard "mil surplus" 150gn ball ammo, such as the L.C. '52 production that CMP sells, or occasionally, the so-called "Garand-safe" 150gn commercial loads, e.g., Federal or the more recent load from PPU.

For this ammo, is one of these aftermarket plugs even necessary?

Second, some M1 owners have a shorter-barreled "Tanker" model, chambered in either '06 or .308. Some of these have 18" barrels (like mine, which is a 7.62/.308), or 16" barrels - such as the "Mini-G" conversions that Schuff does. He apparently installs a Schuster plug on his Mini-G builds, which, I assume, is to cover a variety of ammo his customers may possibly shoot.

But again, for those guys who have a Tanker, if you're only shooting mil-surplus ball ammo, not the higher-pressure commercial hunting ammo, do you need to use one of these plugs?

Thanks in advance ...

A modified gas plug is not necessary for a rifle shooting ammunition designed for the rifle. The modified gas plugs come in a few different designs and work differently. Just as an example and to answer your question take a look at this design plug from Garand Gear.

Our ported gas plug does NOT vent gas like a vented gas plug. The secret is the hollowed out area in the base of the plug 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.

Using a hollow plug they increase the volume of the gas cylinder. If we look at an M1 Garand standard 30-06 Springfield barrel the distance from case mouth to gas port is about 20". Now take a look at the image in the link showing an actual pressure curve. You do not see pressures like 50,000 or 60,000 psi but numbers like around 1,200 psi. When we cut a barrel down (shorten it) the distance between case mouth and gas port hole decreases and the actual pressure at the gas port hole increases. Because of this the guys making this plug state:

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 port pressures that are many times higher then a M1 Garand was ever designed to operate with. The ported design is not suitable for use in this application.

For the short barrel rifles I would think the Schuster Plug Design is the way to go. Designs like this that bleed gas would be the better choice.

Long before these plugs came along many match shooters would modify their own gas plugs by drilling a small diameter hole down the plug center line. While modified gas plugs are match legal in some matches they are not legal in all matches. For those considering match shooting make sure you check the match rules.

Ron

 

[cfullgraf]

In addition to what Reloadron said...

In my standard M1 Garands, I only shoot military surplus or hand loads with an apprpriate powder (I use H4895 or Varget for the most part).

I do not use a pressure relief plug in any of them.

I do not have a tanker model or any experidnce with one.

 

[agtman]

Reloadron & Cfullgraf: Appreciate your responses. Thanks!

 

[Reloadron]

I always enjoy SlamFire1's post in threads like this. His post are always informative and more important well illustrated. SlamFire1 has a great library of blown up guns.

For anyone interested this link is an exert from Hatcher's Notebook (Julian S. Hatcher). Hatcher gets into the strength of military rifles with a strong focus on receivers. If you start at the very bottom of page 205 in the link Hatcher mentions Mr. John C. Garand and his US Rifle Caliber .30 M1 rifle. Garand went through great lengths testing his rifle's strength. The material in the link is a good read for those into this sort of thing. Also worth noting is there was a "Blue Pill" before Viagara was invented.

Just saw Chuck's post and I do about the same. I use standard issue gas plugs and roll my own ammunition for my Garands. For those interested in hand loading 30-06 for this rifle Hornady has a section in their manual devoted to 30-06 service rifle loading. This link covers the Hornady load data. A Google of M1 Garand Load Data will bring up several other sources of hand loading data.

Ron

 

[Merle1]

There's also a third type, the ported gas plug, by Garand Gear. No adjustments necessary.

The manufacturer has done extensive pressure tests on commonly available .30-06 ammunition. You can see that some of the commercial .30-06 tested falls within LC M2 ball specs, without the need for a replacement gas plug.

Be advised that these ammo tests are only reliable for the ACTUAL LOTS TESTED as manufacturers use non-canister grade powders and then blend the powder mix to get the velocity desired. The results may or may not give similar pressure curves. You can get a false sense of security and still damage your rifle.