Finally got my ballistician to do a comment about our testing various different milsurp and commercial ammo in/for the garand to disprove the longstanding M2 ball only myth.

His comments are below...

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I....have been meaning to write a book about this. From my earliest days of being a DCM shooter of M1 Garands on the weekends, to being mentored by old Marines, to being an AMU shooter, to working in Technical Services and Research and Development at St. Marks Powder.....to eventually owning and operating my own internal ballistics laboratory....I have heard of the "theory" of the bent-op rod in the M-1 Garand.

...in the early 2000's, I befriended OLD engineers from Rock Island, Winchester, CCI, and other government and industry locations. NONE of them could confirm "the theory". NONE of them had ever SEEN a bent op-rod. Despite all the parroting, the claims, the "assurances" from crusty old M-1 Garand shooters....even the oft quoted "This ammo is MADE for the M-1 Garand".....

So, being in the position of owning a SAAMI member laboratory, and having every means to run a thorough test....I did.

There are a LOT of nuances involved in ballistic testing. And honestly, if you REALLY want to challenge me on knowledge....bring your lunch. So, I'm not going to get into the "50,000 psi discussion". You quote that in an argument, and you clearly are an arm-chair Ballistician, without modern day knowledge. Study up.

Just a few Cliff notes, before I do the data-dump: I made a "blue pill" load, that approximated the current "Maximum Probable Sample Mean" for 30-06 Springfield SAAMI ammunition. This is the HIGHEST "production" pressure, as statistically suggested within SAAMI documentation for piezo transducer testing. That pressure (MPSM) is 63,800 psi. Note: Max Average Pressure (MAP) for 30-06 Springfield is listed at 60,000 psi Piezo...The intent of this portion of the exercise was to attempt to maximize PORT pressure, while keeping CHAMBER pressure within the realm of "safe limits". Surely, all would agree that IF chamber pressure were pushed FAR above "normal limits"....any damned fool could break a gun, in any number of places.

Back to the maximization of PORT pressures, just to drive the point home: The intent was to find ANY combination of projectile and propellant that would MAXIMIZE port pressure, while keeping inside "reasonably safe" SAAMI chamber pressures. Some would believe it would be "heavy bullet"....and some would believe it would be "slow powder". Well....I ran that experiment for days...turns out a little 130 grain bullet, with 70 (SEVENTY) grains of a fairly slow propellant DID maximize port pressure. Higher than any heavy bullet did....

A formal test barrel was fabricated by SATERN barrels, conforming to the min-spec dimensions of a 30-06 government test barrel chamber, bore cross-section, and port location from the muzzle. While not a "SAAMI" test barrel (but rather conforming to government drawings), it met the intent of the program. Using this test barrel, I created the "blue pill"....and tested ALL ammunition lots of both government and commercial 30-06 ammunition.

Surely some here will reference a group of gentlemen who DID instrument a true M-1 Garand with a piezo transducer TO THE GAS PORT CYLINDER of an M-1 Garand. And...they reported pressure results. Mmmmmyep. Good for them. I did that too. But I did not report those numbers, as there is NO standardized method or equipment to test/capture those numbers. Suffice it to say, that when taking into account PV=nRT, any VARIANCE IN VOLUME of the cylinder will drastically affect the recorded pressure output. Thus, the gas-port cylinder test is inherently flawed, when compared to standard industry methods. MY pressure output numbers utilized industry-standard methods, whereby the pressure is read DIRECTLY at the location of the port (as-per EPVAT modern day methodology), with no associated "free volume" to dampen the output results.

An M-1 Garand rifle was purchased from CMP, with both a "service" grade barrel, as well as a new Criterion barrel...several trigger groups, several op-rods...all with the intent to destroy this firearm by shooting the "blue pill" through it repeatedly.

Findings:

Folks have claimed (totally incorrectly) that heavy bullets....or slow powders....or SAAMI MAP pressures....will doom your M-1 Garand to certain destruction. Folks- I have passed my results to other SAAMI member laboratories, and major ammunition manufacturers. All of them have told me that they've never witnessed ANYONE ELSE, EVER test this system so exhaustively.

The "Blue Pill" load did NOT destroy any part of the M-1 Garand. I've fired in excess of 200 "Blue Pill" rounds through it (along with every other type of commercial and government ammunition), and there remains NO sign of fatigue, or of failure to feed/fire/extract. I have also fired hundreds of rounds of 200+ grain projectiles through this rifle. NO PROBLEM, if the load is kept to SAAMI pressures.

The M-1 Garand is a ROBUST firearm design, able to digest standard SAAMI modern-day ammunition, of any make, and any components, when loaded to SAAMI standard pressures.

I have long offered a bounty for a bent or broken op-rod. I NEED to examine one...but no-one has ever EVER claimed to have had one. The constraints: It must have bent or broken with a load that conforms to SAAMI chamber pressures. The op-rod must be of original non-altered condition (before it was bent). If a hand-load, I must be provided the reloading recipe.

Despite my better judgement, the attachment provides EVERYONE my raw data, proving the extent of the testing across the ocean of time, disparity of manufacturers, and methods of pressure generation. Everything herein is fired out of the pressure barrel, using modern day piezo electric transducers of industry standard, filtered low-pass Bessel active at 20kHz, the transducers and charge amps all calibrated with a dead-weight tested.




UPDATE #1
(From Ken)
Folks- PowderMonkey here again (Ken Johnson of Prospector Training, LLC). We found the attached results sheet containing more data than before. I attach it here, for historical perusal. Should anyone wish to use this information for commercial purposes, I ask (kindly) that they contribute to making me whole. I may be found on the internet, or in Crawfordville, FL.

Jeremy Cheek and I performed this testing at the laboratory. We utilized many of his M1 and M2 lots, dating all the way back to...1927! He freely donated this ammunition, so that others might be able to better understand the TRUTH of the M1 Garand, ammunition loaded and certified for the weapon (over many years), as well as modern day alternatives.

Link to raw data.

https://pink-nonna-70.tiiny.site

In before all the boomers piss and moan about M2 ball being the only thing you can shoot....

Joking aside (not really), great work and appreciate the data.

Very interesting to read. Thank you.

This is wonderful info. Now i just need to purchase a garand with a person to show me whats good vs bad buy

That's an interesting read. Who is the author of the study?

This is very interesting to me, I bought a CMP M1 early this year.  And, like all my firearms, I shoot them.  I load my own Ammo, and I did not shoot it for a couple weeks because I was getting around to making some ammo. I did and do have some 30-06 laying around.  I am going to shoot some 30-06 commercial ammo, see how it goes.  

Attached File


Based on this data, varying weight projectiles doesn't really matter, when it comes to an op rod problem, as long as you stay within 30-06 SAMI pressures of the 30-06 chamber.  But what is ideal weight projectile for the twist of the Garand? If we are not limited to M2 Ball, 150 gr per the folklore.

Probably continue to make Ball M2 ammo for plinking with a soft shooter and when I want to reach out I will use 30-06.

Logically, I don't see why I did not just do this before.  Obviously the chamber can handle full loads, no one ever mentions that as the reason for not shooting 30-06 ammo.  Thinking about it, do I even care if the op rod bends? Just replace it, right?

" The M-1 Garand is a ROBUST firearm design "

This may not be 100% relavant to the thread but am I right that at some point there were tests done to try and destroy an M1 Garand? Maybe under the auspices of Mr. Garand himself and it took some incredibly high powered loads to finally break a lug on the bolt. The bolt was replaced and they resumed testing.

That is probably the definition of "a ROBUST firearm".

I am one of those who heard (and repeated) the old "civilian ammo will damage a garand.  So, this is very interesting.  OK, for this weary boomer who isn't into learning ballistics what is his final finding?  For those of you into the technical side of this stuff HOW robust is the Garand?

https://www.ammoman.com/3006-springfield

Damn, but those 135 grain SMK's are HUMMING going down range.  I can only imagine what kind of damage they'd do compared to some little M193 55 grain bullet plodding down range at  a mere 3150fps (3465 ft lbs vs 1211 ft lbs)

Great work OP.  Always fascinating to see some of the talent that's out there.

After reading, I was really excited to see the results…then found no HXP .

That is ok, it is great info and the data correlates somewhat to others so I can get an idea where HXP would stand.

Is AreaB the area under the port pressure curve?

So I can shoot whatever ammo I want?

After seeing those M2 velocities it looks like my 150 fmjbt  that I load with 3031 & 4895 clocking 2800-2850 through the 03A3 will be ok in the M1.

We were going to shoot HXP but got short on time and after nothing we had shot was giving us any real surprises we skipped it and went to commercial ammo as we figured we had a good example of milsurp velocities for a baseline.

Yes area B is under the port.

Velocity isn't an issue...choot'em Elizabeth!

To me the area under the port pressure curve is how I would rank the ammo from highest to lowest. The pressure amount and time it is applied is more of an indication of how much energy is put into the gas cylinder. Larger slower bullets move up slightly on the list since the pressure is held slightly longer at the port. However, many people would not try to understand that and it does not reorder the data much.

True ..and nanoseconds of extra pressure (dwell) aren't going to change the results.

The point is this thing is and has been way overblown... even moreso since the silly inrange video.

UPDATE #1
(From Ken)
Folks- PowderMonkey here again (Ken Johnson of Prospector Training, LLC). We found the attached results sheet containing more data than before. I attach it here, for historical perusal. Should anyone wish to use this information for commercial purposes, I ask (kindly) that they contribute to making me whole. I may be found on the internet, or in Crawfordville, FL.

Jeremy Cheek and I performed this testing at the laboratory. We utilized many of his M1 and M2 lots, dating all the way back to...1927! He freely donated this ammunition, so that others might be able to better understand the TRUTH of the M1 Garand, ammunition loaded and certified for the weapon (over many years), as well as modern day alternatives.

Link to raw data.

https://pink-nonna-70.tiiny.site

I still wish some ammo company would make M1 Ball again.
I'm not in a position to handload it myself, not yet anyway. And projectiles look to be...uncommon.

It probably wouldn’t be too hard to make an equivalent load. Any of the 175gr Match bullets would be pretty close, the original bullets probably varied that much in weight anyway.

All you’d have to do is match the velocity, which is typically plus or minus 50 fps anyway.

If you really wanted to be persnickety, there are some 173gr FMJBTs out there. They used that bullet in the M72 match and the M118 (not the M118LR). From what I read, they used IMR1185 powder for that load, which was discontinued in 1938. Most of the powders from that time period were replaced with powders that we’re familiar with. I’m not sure what they replaced it with.

I happened into some pretty cheap 10-12 years ago. I loaded them as a cheaper bullet for my .308 match loads-no noticeable difference ballistically to 175gr SMKs out to 400 at least(didn’t try them past that-that’s where I’d use the Sierra bullets) to the point of not even having an appreciable zero shift. That’s why I’d recommend the 175gr match bullets, they’re readily available and more consistent than the originals.

As posted above... get any of the 174-175s out there... load to 2700fps at the muzzle.

I like 48.0 varget and a 175 SMK.  Play with that load up or down a touch your rifle will shoot that better than any M2 ball load.

I appreciate the pointers on loading. Unfortunately, for a variety of big reasons (living situation, family issues at home, work schedule, etc) loading my own is not in the realm of possibility right now. Which was why I was pining for commercially loaded ammo.

That said, I'm definitely taking notes for the future here. Hopefully I can swing a change in circumstances within the next few months, which will open the door to loading my own.

It isn't the best time to start reloading due to the supply situation.  But still a good hobby to pick up.

My brother who got me started in handloading, was a serious scrounge, and we would put nearly any powder and bullet combo we could find in our M1’s and never had a problem. I will say however we are conservative loaders and always loaded a hair above whatever minimal load functioned the guns. It was not unusual for us to use reloading manuals printed in the 1930’s and powders which were discontinued before WWII.
I have seen your posts here before, and agree the M1 is not some weakling to be treated with kid gloves