M2 Ball

[mikejonestkd]

I have made no claims in this thread. The burden of proof is on you.

 

[Jeremy2171]

I have made no claims in this thread. The burden of proof is on you.

Figures..if you can't post that there is a limit....then there no max allowed velocity.


That's how it works. There is no weight limit or velocity limit on the garand. Ask the govt.

 

[Unclenick]

Jeremy2171,

You are correct that there is no single bullet weight or single velocity limit because that's not how the weapon or ammunition is specified by the military. However, that's not the same as saying you can fire any bullet weight at any velocity without causing damage to the gun. Operating rod bending and chamber and brass peening are the common concerns from pressurizing the gas port too high with too much dwell time (time for the bullet base to go from exposing the gas port to pressure to exiting the muzzle and letting pressure drop).

John C. Garand himself was aware of this limitation of the gun design, as he patented a vented gas port plug for the Garand in 1942, specifically to address this problem (patent drawing below) by venting some of the gas cylinder pressure as it rose. The gun, as designed, was able to handle M1 Ball ammunition and the later M2 Ball and M2 AP ammunition without modification, though.

 

[Jeremy2171]

Jeremy2171,

You are correct that there is no single bullet weight or single velocity limit because that's not how the weapon or ammunition is specified by the military. However, that's not the same as saying you can fire any bullet weight at any velocity without causing damage to the gun. Operating rod bending and chamber and brass peening are the common concerns from pressurizing the gas port too high with too much dwell time (time for the bullet base to go from exposing the gas port to pressure to exiting the muzzle and letting pressure drop).

John C. Garand himself was aware of this limitation of the gun design, as he patented a vented gas port plug for the Garand in 1942, specifically to address this problem (patent drawing below) by venting some of the gas cylinder pressure as it rose. The gun, as designed, was able to handle M1 Ball ammunition and the later M2 Ball and M2 AP ammunition without modification, though.

JCG designed that for use with "Ammunition which develops pressures considerably in excess of normal operating pressures".

Currently commercial ammo doesn't create excessive pressure compared to milsurp.

Secondly his patent was never adopted...as it's not needed.

Chamber and brass "peening "?

Oprods are "bent" due to lack of lubrication. By the time the oprod begins to move the bullet is 7" out of the bore...and the system is already depressurizing.

 

[Unclenick]

Oprods are "bent" due to lack of lubrication.

It's one source of the problem, but not the only one. Steel has limited stress cycle life. The more stress in each cycle, the fewer cycles you get out of it. Our Garand op-rods are mostly getting old now and have been through many firing cycles. Also, if you've done some rebuilding, you'll have run into the common hard carbon cake buildup under the Stainless piston head that often covers significant corrosion pitting from back in the corrosive primer ammo days. The aging op-rods are simply not as strong as they once were, which is another reason to be kind to them by using a gas cylinder pressure mitigating device.

By the time the oprod begins to move the bullet is 7" out of the bore...and the system is already depressurizing.

The pressure in the barrel takes some time to drop below the pressure in the cylinder. Indeed, most of the pressurization of the cylinder happens after the bullet is gone and over a period of about four milliseconds before the barrel pressure drops below the cylinder pressure and stops feeding gas to it. Force begins to be applied to the piston head as soon as any pressurizing starts to occur, of course. If the op-rod handle isn't moving yet, you need to think about what the stress from the op-rod and spring inertia holding back that pressure is doing to the shape of the rod and how the resulting deformation transmits down the rod. Basically, you are creating a traveling bulging deformation by starting to move the piston head back before the handle starts to move. This depends on the elasticity of the tubing steel to handle the deformation, and it gradually fatigues the steel.

Currently commercial ammo doesn't create excessive pressure compared to milsurp.

Peak chamber pressure can be remarkably independent of gas cylinder peak pressure. Rather than me explaining it, please read through this article at Garandgear.com. It has actual high-speed gas cylinder pressure data and walks you through what happens in the gas cylinder as a sequence and has commercial ammunition data that shows most commercial 180-grain (and heavier) bullet loads and at least one 150-grain load (Fiocchi Extrema) exceed the highest surplus M2 Ball gas cylinder pressure they measured (LC66) in establishing a baseline for the testing. One critical point mentioned is that the faster a bullet goes, the shorter the pressure impulse driving gas into the cylinder lasts. This is why a powder that would over-pressurize the cylinder with a heavy bullet may not do so with a lighter bullet driven to the same muzzle energy. Reading that whole long article is worthwhile.

The fact greater bullet speed mitigates gas cylinder pressure is something that seems not to have been clear to the military when 30-06 ammo was being developed and tested for the Garand, which I infer from how the ammunition specs are written. They didn't have high-speed data acquisition systems when the gun was designed and had to rely on other forms of evaluation. For example, in 1972, when Olin Mathieson's lot BAJ 47287 of WC852 was loaded to meet the M2 Ball 2740±30 fps velocity limits, it needed a charge of 60.1 grains. This developed a peak chamber pressure of only 40,200 psi (by copper crusher), but it was DQ'd for the Garand but allowed for loading 30-06 for the three machinegun models that M2 was still used in at the time. With that low peak pressure, achieving the required velocity required continued acceleration by greater post-peak or late barrel pressure developed by the large gas volume made by the slow-burning powder's large charge. That resulted in correspondingly higher muzzle pressure which worried Lake City. The standard lot of WC852 used only 50 grains to get to the required velocity window.

HOWEVER, the DQ was probably not justified for M2 Ball because of the weight of the bullet, which clears the muzzle quickly, meaning the gas behind it is also moving out quickly and will drop pressure sooner after the bullet leaves. Years later, when that ammo was all the training ammo that was left for the DCM to use in the Garand, the op-rod velocity it produced was measured (an indirect gas impulse evaluation) and found not to be anything unusual for the gun, so it was de-linked and put into Garand clips. However, DQ'ing that lot for M2 AP would be another matter and might have been justified by the higher pressure and slower velocity resulting from the heavier bullet. I am just speculating there, and it would have to be measured to find out.

Chamber and brass "peening "?

 

[105kw]

In 1985, after I got out of the service, and got a good job. I decided I needed an M-1 Garand to go with my 1903 Springfields.
I bought an M-1 that had been set up for match shooting. Glass bedded, and with some NM parts. The estate sale included a range box, and a good supply of .30M2, and reloads with 190gr Match Kings, and some 168 MK.
A friend at a local gunshop, gave me a Field Manual, and a lessen on what and how much to lube.
My first misconception was that all the ammo I had was loaded for the Garand.
I went out to the range to test fire.
Accuracy was really good the 190s were loaded with a IMR 4831 and a charge of 55gr.
They shot into 1.5 inches at 100.
After about 60 rounds, I was getting about 3-4 inch groups.
Realizing I had a problem, I immediately headed to then nearest Gunsmith. Does anybody remember Shooters Supply in Yakima?
End result, a new op rod, and an NRA publication on Shooting and Reloading for an M-1.
Hornady Reloading Manual, has a separate section for the M-1 to keep the pressures and bullets in tolerance to the Garand.
Keep the bullet weight 150gr to 178, with recommended powders, your good.

 

[Unclenick]

Sorry you had to learn that the hard way. A match Garand builder I used to know slightly would just shake the assembled rifle in his hand and declare "good op-rod" or "dead op-rod." I never quite figured out what he was looking at or feeling.

You can, incidentally, get refurbished op-rods, where someone has cut the pitted part under the piston head away and silver-brazed a new piston head in place. I picked several op-rods up on Commercial Row at Camp Perry one year and, comparing lengths, discovered I had got one of those. My first reaction was to be annoyed, as it would throw the recoil spring a little out of calibration. But my second thought was that it would mitigate accidental high gas cylinder pressures like you got, based on the same principle as the Garand Gear hollowed-out gas cylinder plug.

 

[Jeremy2171]

It's one source of the problem, but not the only one. Steel has limited stress cycle life. The more stress in each cycle, the fewer cycles you get out of it. Our Garand op-rods are mostly getting old now and have been through many firing cycles. Also, if you've done some rebuilding, you'll have run into the common hard carbon cake buildup under the Stainless piston head that often covers significant corrosion pitting from back in the corrosive primer ammo days. The aging op-rods are simply not as strong as they once were, which is another reason to be kind to them by using a gas cylinder pressure mitigating device.

Not really as the only real stress on the oprod is at the cam angle and handle area.

The pressure in the barrel takes some time to drop below the pressure in the cylinder. Indeed, most of the pressurization of the cylinder happens after the bullet is gone and over a period of about four milliseconds before the barrel pressure drops below the cylinder pressure and stops feeding gas to it. Force begins to be applied to the piston head as soon as any pressurizing starts to occur, of course. If the op-rod handle isn't moving yet, you need to think about what the stress from the op-rod and spring inertia holding back that pressure is doing to the shape of the rod and how the resulting deformation transmits down the rod. Basically, you are creating a traveling bulging deformation by starting to move the piston head back before the handle starts to move. This depends on the elasticity of the tubing steel to handle the deformation, and it gradually fatigues the steel.

You think a small spring is resisting the gas pressure enough to cause travelling bulging deformation down the tube?

That's quite an imagination you have there....

Peak chamber pressure can be remarkably independent of gas cylinder peak pressure. Rather than me explaining it, please read through this article at Garandgear.com. It has actual high-speed gas cylinder pressure data and walks you through what happens in the gas cylinder as a sequence and has commercial ammunition data that shows most commercial 180-grain (and heavier) bullet loads and at least one 150-grain load (Fiocchi Extrema) exceed the highest surplus M2 Ball gas cylinder pressure they measured (LC66) in establishing a baseline for the testing. One critical point mentioned is that the faster a bullet goes, the shorter the pressure impulse driving gas into the cylinder lasts. This is why a powder that would over-pressurize the cylinder with a heavy bullet may not do so with a lighter bullet driven to the same muzzle energy. Reading that whole long article is worthwhile.

I'm not worried about the GG article.
As I've oft pointed out..the GG test data is flawed (on purpose?) because they used LC66 as a baseline and it's some of the weakest M2 ball out there. had they tested a larger variety of M2 ball ammo they would have seen that the pressures in commercial and milsurp ammo aren't that different. But if the data presented showed commercial ammo was similar pressure wise...then you wouldn't want to buy his little gizmo he copied from the Italians. He provides the test data that shows you NEED his product....think about that.

The fact greater bullet speed mitigates gas cylinder pressure is something that seems not to have been clear to the military when 30-06 ammo was being developed and tested for the Garand, which I infer from how the ammunition specs are written. They didn't have high-speed data acquisition systems when the gun was designed and had to rely on other forms of evaluation. For example, in 1972, when Olin Mathieson's lot BAJ 47287 of WC852 was loaded to meet the M2 Ball 2740±30 fps velocity limits, it needed a charge of 60.1 grains. This developed a peak chamber pressure of only 40,200 psi (by copper crusher), but it was DQ'd for the Garand but allowed for loading 30-06 for the three machinegun models that M2 was still used in at the time. With that low peak pressure, achieving the required velocity required continued acceleration by greater post-peak or late barrel pressure developed by the large gas volume made by the slow-burning powder's large charge. That resulted in correspondingly higher muzzle pressure which worried Lake City. The standard lot of WC852 used only 50 grains to get to the required velocity window.

Haven't seen an official documentation that supports that.

HOWEVER, the DQ was probably not justified for M2 Ball because of the weight of the bullet, which clears the muzzle quickly, meaning the gas behind it is also moving out quickly and will drop pressure sooner after the bullet leaves. Years later, when that ammo was all the training ammo that was left for the DCM to use in the Garand, the op-rod velocity it produced was measured (an indirect gas impulse evaluation) and found not to be anything unusual for the gun, so it was de-linked and put into Garand clips. However, DQ'ing that lot for M2 AP would be another matter and might have been justified by the higher pressure and slower velocity resulting from the heavier bullet. I am just speculating there, and it would have to be measured to find out.

That powder wasn't loaded in M2 AP so not relevant. I also believe the slow powders in garands is also way overblown considering those Early 70's lots of M2 ball have similar port pressures as commercial ammo. Heck "garand safe" ammo by PPU and S&B have higher port pressures than most milsurp ammo.

That says it's looking for problems in the chamber such as from a defective chamber reamer.

 

[44 AMP]

The M1 Garand, like every other semi auto is made to run on a certain "fuel" and while some variance from the design intent ammo can work, if you go too far away from what it was built to use, like any tuned engine, performance WILL suffer, and damage may result.

Remember that, as a service rifle, the military has a large support structure of repairmen and parts. AND the military is really only interested in having ammunition that feeds, fires, and ejects properly, ONCE.

Also, consider that a bent op rod, which destroys the match grade accuracy (usually) can still leave the rifle in entirely acceptable "service grade" condition for military use.

And, personally, I think claiming there is no limit is a childish oversimplification. Every piece of machinery has limits, upper and lower, run it outside of them and things don't work right, or even break.

Some machines will tolerate being run outside their operating limits for some time, some will not. All eventually fail in some fashion, before they wear out when operated withing their design specs.

 

[Jeremy2171]

The M1 Garand, like every other semi auto is made to run on a certain "fuel" and while some variance from the design intent ammo can work, if you go too far away from what it was built to use, like any tuned engine, performance WILL suffer, and damage may result.

I love working off of facts. What "fuel" was the garand designed to use?

Remember that, as a service rifle, the military has a large support structure of repairmen and parts. AND the military is really only interested in having ammunition that feeds, fires, and ejects properly, ONCE.

Also, consider that a bent op rod, which destroys the match grade accuracy (usually) can still leave the rifle in entirely acceptable "service grade" condition for military use.

99% of garands out there are service grade guns already..."match" grade garands require work.

And, personally, I think claiming there is no limit is a childish oversimplification. Every piece of machinery has limits, upper and lower, run it outside of them and things don't work right, or even break.

Some machines will tolerate being run outside their operating limits for some time, some will not. All eventually fail in some fashion, before they wear out when operated withing their design specs.

great...point... what IS the design specs?

 

[Unclenick]

Not really as the only real stress on the oprod is at the cam angle and handle area.

Not really. From the pressure readings at Garand Gear, you can see the cylinder pressure reaches about 1100 psi. The head of the piston has an area of about 0.217 square inches. Multiplied by the pressure, that means 239 lbs of force is applied to the piston over about 4 milliseconds. If you imagine a 239-pound person balancing on top of the op-rod with a stub in the bolt camming recess holding it upright, you can then get a sense of what the force trying to bend the op-rod looks like.

If you are puzzled by what the 239 lb force is pushing against in operation, look up Newton's three laws of motion. It is pushing against reaction force due to mass inertia.

You think a small spring is resisting the gas pressure enough to cause travelling bulging deformation down the tube?

That's quite an imagination you have there....

Nope. That's your imagination at work, not mine. I didn't say anything about the spring at all. It subtracts a few pounds from the 239 lbs of applied force at the gas cylinder pressure peak, but that's about it. Overall, it's not a significant factor.

I'm not worried about the GG article.
As I've oft pointed out..the GG test data is flawed (on purpose?) because they used LC66 as a baseline and it's some of the weakest M2 ball out there.

The flaw is you are assuming, without measurement to back it up, that gas cylinder pressure will necessarily have a positive correlation with how hot the load is. While that tends to be true with slow powders, the opposite is often true with fast powders. The LC66 M2 could, indeed, be mild in terms of muzzle velocity, but still, produce higher gas cylinder pressure than a hotter year. On the CMP site, Garand Gear engineer Eric C. had a gas cylinder pressure plot showing three loads of IMR 8208 XBR in the Garand which had a negative correlation to gas cylinder pressure (the cylinder pressure got smaller as the powder charge was increased). This happened because the velocity of the bullet and the gas chasing it were increased more by additional charge weight than the muzzle pressure was. Thus, pressure multiplied by time (the gas impulse driving gas into the cylinder) had a net decrease.

The above supports your contention that warmer loads can be handled by the Garand than some think because the warmer load can actually mean lower gas system pressure, provided the powder burn rate isn't too slow. But without pressure measuring gear, you can't demonstrate comparative levels and know for sure what you are getting.

Haven't seen an official documentation that supports that.

You've never seen an atom, either, but that doesn't mean they don't exist. It just means you haven't seen one. From your peening question, I assume you haven't seen the M2 Ball spec, either, but it exists.

That powder wasn't loaded in M2 AP so not relevant. I also believe the slow powders in garands is also way overblown considering those Early 70's lots of M2 ball have similar port pressures as commercial ammo. Heck "garand safe" ammo by PPU and S&B have higher port pressures than most milsurp ammo.

Your turn to document the evidence and show the measurements and their results. And again, it isn't gas port pressure, but the gas port pressure times the length of time the gas port is exposed to that pressure that determines how much gas is driven into the cylinder and therefore how high the gas cylinder pressure is and how hard it pushes the op-rod.

That says it's looking for problems in the chamber such as from a defective chamber reamer.

Read it again. They are looking for the peening (deformations) to start to appear after firing every single one of the 100 rounds in (D). There isn't any reaming going on between each round, so it is damage done by firing the rounds that they are looking for, not from reaming.

great...point... what IS the design specs?

The exact design specifications are in the blueprints, which you can buy from Nicolaus Associates. If the specification you are referring to is what ammunition the Garand was designed for, Hatcher's Book of the Garand says the military told J.C.G. the gun had to work with stockpiled M1 Ball ammo. A sample of M1 Ball, FA 34, was fired in the Garand Gear tests. M72 has the same nominal bullet weight and velocity specs, (174.5 grains +0/-3 grains tolerance, and 2640 fps at 78 feet from the muzzle), and they also fired some LC64 M72, which produced even less gas cylinder pressure, though that year, IIRC, M72 used just 46.0 grains of a fast lot of IMR4895, so it would be expected to have a higher-than-usual peak-to-muzzle pressure ratio, reducing the relative gas port impulse. All the Garand's ability to handle anything more is due to safety margins designed into the gun, which would have to include handling a few proof loads in its lifetime, but too many would be expected to quickly fatigue the moving parts.

 

[44 AMP]

If the specification you are referring to is what ammunition the Garand was designed for, Hatcher's Book of the Garand says the military told J.C.G. the gun had to work with stockpiled M1 Ball ammo.

ok, now I'm mildly curious, just for information, wasn't the Garand originally designed for the .276 round and adapted to the .30-06 to meet govt requirements??

 

[Jeremy2171]

Not really. From the pressure readings at Garand Gear, you can see the cylinder pressure reaches about 1100 psi. The head of the piston has an area of about 0.217 square inches. Multiplied by the pressure, that means 239 lbs of force is applied to the piston over about 4 milliseconds. If you imagine a 239-pound person balancing on top of the op-rod with a stub in the bolt camming recess holding it upright, you can then get a sense of what the force trying to bend the op-rod looks like.

If you are puzzled by what the 239 lb force is pushing against in operation, look up Newton's three laws of motion. It is pushing against reaction force due to mass inertia.

GG needs to do more testing as their numbers don't match up with SA. They are about 1000 psi to low.

Your 239lb of force is also wrong as only the spring is holding it in place and it doesn't begin to move until after the bullet has left the bore and the system is already depressurizing.

Once the oprod begins to move it has even less pressure on it and the main resistance is from trying to unlock the bolt and extract the casing. No lube on the oprod cam and bolt load increase this load quite a bit and this is where the damage comes from.

Nope. That's your imagination at work, not mine. I didn't say anything about the spring at all. It subtracts a few pounds from the 239 lbs of applied force at the gas cylinder pressure peak, but that's about it. Overall, it's not a significant factor.

See above

The flaw is you are assuming, without measurement to back it up, that gas cylinder pressure will necessarily have a positive correlation with how hot the load is. While that tends to be true with slow powders, the opposite is often true with fast powders. The LC66 M2 could, indeed, be mild in terms of muzzle velocity, but still, produce higher gas cylinder pressure than a hotter year. On the CMP site, Garand Gear engineer Eric C. had a gas cylinder pressure plot showing three loads of IMR 8208 XBR in the Garand which had a negative correlation to gas cylinder pressure (the cylinder pressure got smaller as the powder charge was increased). This happened because the velocity of the bullet and the gas chasing it were increased more by additional charge weight than the muzzle pressure was. Thus, pressure multiplied by time (the gas impulse driving gas into the cylinder) had a net decrease.

LC 66 is mild in the realm of port pressure. There fore its a poor benchmark.

The above supports your contention that warmer loads can be handled by the Garand than some think because the warmer load can actually mean lower gas system pressure, provided the powder burn rate isn't too slow. But without pressure measuring gear, you can't demonstrate comparative levels and know for sure what you are getting.

testing of commercial ammo has already shown similar oprod velocities as milsurp ammo.

You've never seen an atom, either, but that doesn't mean they don't exist. It just means you haven't seen one. From your peening question, I assume you haven't seen the M2 Ball spec, either, but it exists.

I have the M2 ball specs so I know it exists. I was just calling out your claim without lack of documentation.

Your turn to document the evidence and show the measurements and their results. And again, it isn't gas port pressure, but the gas port pressure times the length of time the gas port is exposed to that pressure that determines how much gas is driven into the cylinder and therefore how high the gas cylinder pressure is and how hard it pushes the op-rod.

The push on the rod isn't the issue...the real issues is how much friction and resistance it meets in it's travels.

Read it again. They are looking for the peening (deformations) to start to appear after firing every single one of the 100 rounds in (D). There isn't any reaming going on between each round, so it is damage done by firing the rounds that they are looking for, not from reaming.

it would be interesting to see a chamber peened by an otherwise in spec round.

The exact design specifications are in the blueprints, which you can buy from Nicolaus Associates. If the specification you are referring to is what ammunition the Garand was designed for, Hatcher's Book of the Garand says the military told J.C.G. the gun had to work with stockpiled M1 Ball ammo. A sample of M1 Ball, FA 34, was fired in the Garand Gear tests. M72 has the same nominal bullet weight and velocity specs, (174.5 grains +0/-3 grains tolerance, and 2640 fps at 78 feet from the muzzle), and they also fired some LC64 M72, which produced even less gas cylinder pressure, though that year, IIRC, M72 used just 46.0 grains of a fast lot of IMR4895, so it would be expected to have a higher-than-usual peak-to-muzzle pressure ratio, reducing the relative gas port impulse. All the Garand's ability to handle anything more is due to safety margins designed into the gun, which would have to include handling a few proof loads in its lifetime, but too many would be expected to quickly fatigue the moving parts.

And it was designed for all 30 cal service ammunition. So any commercial ammo with similar operating pressures is also safe.

 

[Jeremy2171]

ok, now I'm mildly curious, just for information, wasn't the Garand originally designed for the .276 round and adapted to the .30-06 to meet govt requirements??

Nope...30-06 first...then .276 then back to .30-06

 

[Bart B.]

The most accurate Garands were probably those rebarreled by the US Navy to 7.62 NATO. Those with groove diameters under .299 inch were match conditioned and tested at 600 yards with hand loaded Sierra 190 HPMKs. Those testing under 4 inches were used by the top team at top levels of competition.

 

[akinswi]

Nope...30-06 first...then .276 then back to .30-06

https://www.thearmorylife.com/276-pedersen-and-the-other-garand/

Interesting article between the two. Fast forward almost 100 years later I always wondered how accurate this cartridge would have been, but accuracy vs lethality but a 7mm bullet is no joke either which is basically what the 276 is.

But the rotating bolt design was key for Garand vs the lubrication ammo was the downfall of the 276

 

[Jeremy2171]

https://www.thearmorylife.com/276-pedersen-and-the-other-garand/

Interesting article between the two. Fast forward almost 100 years later I always wondered how accurate this cartridge would have been, but accuracy vs lethality but a 7mm bullet is no joke either which is basically what the 276 is.

The .276 would have been a neat "what if".

Its very light and handy to hold. Almost like a bigger M1 carbine. I could get used to toting one.

 

[akinswi]

Not to Mention M1 ball which had far better range than the M2 ball . which is another controversy.

 

[akinswi]

Bart B is correct, I believe they to even had shrink the target size of the NRA targets because the 7.62 nato was more accurate than the 30-06.

But I always felt M1A for 7.62 and 30-06 for M1 . Just my preference

 

[Jeremy2171]

Not to Mention M1 ball which had far better range than the M2 ball . which is another controversy.

I wouldn't call it a controversy...just tactics changed and the M1906/M2 round was primarily intended for training while the AP was the primary combat ammo.

The M1 was very accurate but also expensive to make.