Loading M2 in 30-06?

CAUTION: The following post (or a page linked to) includes or discusses loading data not covered by currently published sources of tested data for this cartridge (QuickLOAD or Gordon's Reloading Tool data is not professionally tested). USE AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL assumes any liability for any damage or injury resulting from the use of this information.

ran a few numbers this morning in GRT this morning
It is estimating a max of 57.4 at 2836fps
to match the 2763fps velocity, 56.0g would give me 2764fps

Again, granted this is all GRT data. but at least it give me a ballaprk to look at.
 
Shadow9mm said:
CAUTION: The following post (or a page linked to) includes or discusses loading data not covered by currently published sources of tested data for this cartridge (QuickLOAD or Gordon's Reloading Tool data is not professionally tested). USE AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL assumes any liability for any damage or injury resulting from the use of this information.

ran a few numbers this morning in GRT this morning
It is estimating a max of 57.4 at 2836fps
to match the 2763fps velocity, 56.0g would give me 2764fps

Again, granted this is all GRT data. but at least it give me a ballaprk to look at.
Click to expand...
When doing my garand ammo pressure testing I found that quickload was "close enough" to my results from the pressure test barrel that I could look at QL numbers and see how reload data would match up if fired in a garand.
 
Did some measuring, touching the lands I had an average of 3.318. Going to seat at 3.300 even, should be adequate bullet jump.
 
The issue with the Garand has never been about the ability of the action or barrel to tolerate the peak pressures of whatever you put into it. It's super-strong, and no commercial, nor even a particular warm lot of M2 AP that turned out to exceed the SAAMI numbers, would ever be a threat to it. The issue has always been about operating rod fatigue. That comes from gas impulse driving gas into the gas cylinder, not peak pressure. For any given peak pressure, a slower powder generally will require more powder, and burning more powder means making more gas, so muzzle pressure tends to be higher. When, instead of peak pressure, you focus on a fixed velocity, the tendency is still to require a somewhat greater charge weight of the slower powder. Therefore, you get that velocity from a combination of lower peak pressure and higher muzzle pressure, such that it provides the same average pressure during barrel time. The gas impulse applied to the gas port on the bore side is then the average pressure multiplied by the time for which that pressure is applied to it. This is mostly during the time the back end of the bullet bearing surface takes to travel from the gas port to the muzzle, plus the time and average pressure from the moment the bullet bearing surface exits the muzzle until the pressure in the bore drops to a value lower than the pressure inside the gas cylinder. This is further complicated by the fact that gas flow through an opening like the gas port can undergo a choking effect if its flow velocity exceeds the speed of sound in the hot gas. This makes it a lot easier to simply measure gas cylinder pressurizing than to calculate the effect.

Eric at Garandgear.com has done a lot of these measurements using a fast diaphragm transducer mounted in a gas cylinder plug. It lets you see what the commercial loads actually do. Most are no more than 12% over maximum M2 Ball numbers.

All of that adds up to it being difficult for immediate damage to occur to an op-rod in good condition or to a receiver heel. But they will fatigue faster, so it will shorten service life. I've done frame counting of some of a YouTube video showing side-by-side slow-motion op-rod cycling that illustrated about 20% more speed from one commercial load than from M2, IIRC (can't find it at the moment). The stopping force needed to stop the op-rod's rearward motion will be proportional to its kinetic energy, and its kinetic energy will be proportional to the square of its velocity. So the 20% faster op-rod was subjected to 44% more stopping force when it tapped the back of the receiver. That will eventually promote receiver heel cracking.

So, the issue is simply that the gun will wear out sooner with high gas impulses. It's not that it can't handle them for a while. I like the Garand Gear gas port plug solution as it lets you shoot anything without adding fatigue speed. Indeed, it reduces fatigue even for regular M2 and similar Garand loads and makes your brass eject closer by. A properly tuned ported gas plug like J.C. Garand's post-war design or the various commercial versions will do the same thing, but you have to adjust them for each load, whereas the Garand Gear device is one-and-done for all loads.
 
Unfortunately that testing at garand gear is very narrow and didn't cover a wide variety of milsurp ammo. If he has done a larger reference sample he would have seen that only a few types of commercial ammo are higher than the highest milsurp and by only like 5% or so.


The video you are talking about and getting the large difference in bolt speed was done using the weakest M2 ball loading out there ...most likely LC 69.

When running that commercial ammo against "garand safe" ammo they moved at the same speed. That why the inrange/Ian video is pretty much worthless for any scientific data.


So it's back to proper lubrication and keeping your oprod spring at least 19.5" long is the easiest this to keep your rifle running for decades.
 
/me wonders why no one ever built a pressure relief valve (ball and spring type) to screw into the end of the gas chamber. it could hold all of the gas in on loads that did not exceed the max pressure; and, dump all gas above that pressure, it could dump it at a 10 degree deflection both right and left of straight forward to avoid blacking the front sight... just seems to make to much sense i guess.
 
For reference this load will NOT be being used in a Garand, as previously stated. Gas port pressure an op rod speeds are cool, but rather a bit off topic for this specific thread in light of that. If we could get off that topic it would be appreciated.

Hoping to do chronograph testing Friday, weather permitting.
 
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Jeremy2171,

Shadow9mm has a point that this thread has drifted off-topic. But your post is valuable, so I am going to move it to start a separate thread. Then, later in the day, I will add how I concluded the crop of usual "Garand loads" are off-base, as I have posted on the CMP forum in the past, but I got there through a completely different line of reasoning. I'll disagree with you on a couple of points in that new thread, but I will be interested to hear what your reply is (I love a good debate that stays civil), but I am tied up with appointments today, so I may not get to the reply until tomorrow.

Your new thread is here.
 
Quick update. Ran testing today, optical chronograph at about 15ft. Max charge of 57.0g H4350 resulted in a sticky bolt that did not want to open, felt like I was running an over heated Mosin, , and that significant velocity jump. Going to run with 56.2g as 55.6g ran fine and it puts me another 0.4h step down.

H4350 seated to 3.330 CCI #200 large rifle primers, Starline brass. Velocities will vary, only 1 round per charge weight

55.4 2728fps
55.8 2726fps
56.0 2731fps
56.2 2742fos
56.6 2752fps
57.0 2817fps, sticky bolt.
 
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Did you weight and trickle each charge? 4350 is extruded sticks. It happened to me a few times that bridged powder sticks retained some powder from the previous drop and ended up with the next drop with over charge.

-TL

Sent from my SM-N960U using Tapatalk
 
only 1 round per charge weight
Click to expand...

Your sample size is too small to make any valid comparisons or judgements.

By shooting only one round, all that tells you is what that one round did, and that is not enough for a valid comparison, as you have nothing to show that the one round fired is not a fluke.

None of us on a budget (or even those who aren't) likes to "waste" expensive (and sometimes difficult to obtain) components on loads that don't pan out, but it is a necessary evil, to use and them, otherwise, you don't really know what is happening, you're just guessing, and hoping you're right.

You might be right, you might not be, one round isn't going to tell you which it is with any degree of certainty, absent other factors.

And those other factors can be very important. Things like the rifle not operating normally can be valid reasons to discontinue testing after a single round, if they are far outside normal operation. Sticky bolt lift is a big "STOP" sign for me.
 
tangolima said:
Did you weight and trickle each charge? 4350 is extruded sticks. It happened to me a few times that bridged powder sticks retained some powder from the previous drop and ended up with the next drop with over charge.

-TL

Sent from my SM-N960U using Tapatalk
Click to expand...
Yes, I did trickle charge and weight in each charge, have to with stock powders.
 
44 AMP said:
Your sample size is too small to make any valid comparisons or judgements.

By shooting only one round, all that tells you is what that one round did, and that is not enough for a valid comparison, as you have nothing to show that the one round fired is not a fluke.

None of us on a budget (or even those who aren't) likes to "waste" expensive (and sometimes difficult to obtain) components on loads that don't pan out, but it is a necessary evil, to use and them, otherwise, you don't really know what is happening, you're just guessing, and hoping you're right.

You might be right, you might not be, one round isn't going to tell you which it is with any degree of certainty, absent other factors.

And those other factors can be very important. Things like the rifle not operating normally can be valid reasons to discontinue testing after a single round, if they are far outside normal operation. Sticky bolt lift is a big "STOP" sign for me.
Click to expand...

So I understand what your saying and I agree in a way, but I also do not agree.

My primary goal was to check for pressure signs and ensure that my load was within safe limits as best I was able. I believe I was able to reach a definitive answer on that, that 57.0g is too much. 56.6g acted normally, to which I determined that in my rifle 56.6g is max, and I decided on 56.2g as my final load to give and extra safety buffer.

H4350 is a temp stable powder and on the day I did testing it was about 80F outside, so I have no concerns of a pressure increase due to heat.

While I would have loved to shoot more, I only had 56 and I wanted to be able to load and retain 50. If I am somehow able to obtain a few more of these I will shoot at least 1 group over the chrono and for accuracy. but in my limited searching I cannot find any available.
 
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I also use similar procedure for developing my loads. It is controversial. But it is my choice as money is limited. One round with precision charge. I don't see it as sample size of one, but rather 10 with sweeping index. Look for pressure signs. Record MV and poi. I usually have 10 rounds with 1% charge difference. I will pick the spot with minimum vertical poi variation. The next step is coal search in step of 0.002" with 20 rounds. Skipping details, I could reach an ok load in 40 rounds with the last 10 rounds for group verifications.

I do all these at 150yd to give more time for the bullet to settle.

-TL

Sent from my SM-N960U using Tapatalk
 
A 21.5" barrel should lose about 85 fps off the M2 velocity, give or take, as compared to a 24-inch barrel, so M2 should be about 2705 fps at 15 feet from the muzzle for your gun to be seeing about the same peak pressure. However, every load will have a mean and standard deviation value, and to have some idea what the average velocity actually is after you've found the pressure limit, run at least 10 of them (30 is much better, but 10 is what SAAMI uses, so there's no point in trying to be more precise than their baseline is).

Interestingly, your velocities are higher than the Hodgdon data would suggest they should be, but GRT predicts closer to what you have than to what Hodgdon has listed. Conversely, QuickLOAD predicts lower velocities than Hodgdon does. Taken together, this suggests the relative burn rate of the powder has become a bit quicker in recent years. In any event, a range of relative burn rates seem to have been out there and the powder models disagree substantially, with GRT having an energy content of 3900 J/g, vs. 3750 J/g for QL, and the progressivity rate being 0.9683 in GRT, and only 0.2476 in QL. It's like they were testing two different powders. In any event, for the lot of powder you have, I am more inclined to believe the GRT model because it matches the limited data you have better than QL does.

In general, when your gun, after allowing for barrel length difference, gets a lower velocity than the Hodgdon test gun did, it means your peak pressure is lower for the same charge weight of powder. When you get a higher velocity than they do after allowing for barrel length difference, you have higher peak pressure for the same charge weight of powder than they do. This latter condition would agree with what you are seeing by way of a sticky bolt lift. It seems the Hodgdon data is from a lower burn rate lot than you have. I would be adjust down to find a 10-shot average of 2704 fps with your load. Then shoot ten shots for confirmation.

This is just the sort of situation that is the reason we always start with bottom loads and work up, and we don't try to start in the middle somewhere. If you had started with Hodgdon's middle value of 59 grains, you'd have been putting overpressure wear on your gun from the git-go, so good job on not falling into that trap.
 
tangolima said:
I also use similar procedure for developing my loads. It is controversial. But it is my choice as money is limited. One round with precision charge. I don't see it as sample size of one, but rather 10 with sweeping index. Look for pressure signs. Record MV and poi. I usually have 10 rounds with 1% charge difference. I will pick the spot with minimum vertical poi variation. The next step is coal search in step of 0.002" with 20 rounds. Skipping details, I could reach an ok load in 40 rounds with the last 10 rounds for group verifications.

I do all these at 150yd to give more time for the bullet to settle.

-TL

Sent from my SM-N960U using Tapatalk
Click to expand...
To do a load workup that I consider to be excellent it generally means going through a full 100 count box of bullets. But that is not always an option and you can still get more than serviceable results doing less. If you ask Hornady charge weight does not matter until you change a full grain in powder, and seating depth has no effect. Granted I have not done nearly as much testing as they have, but in my limited experience that is not the case.
 
For pressure alone, as you were testing, I also start with single rounds in 2% steps, being careful to tip the gun up to get powder back over the primer for worst-case pressure. Then, I look more closely at pressure when I pick a load to test for velocity. That's usually 10 rounds to start, and more if it shoots well for the first ten.
 
Unclenick said:
A 21.5" barrel should lose about 85 fps off the M2 velocity, give or take, as compared to a 24-inch barrel, so M2 should be about 2705 fps at 15 feet from the muzzle for your gun to be seeing about the same peak pressure. However, every load will have a mean and standard deviation value, and to have some idea what the average velocity actually is after you've found the pressure limit, run at least 10 of them (30 is much better, but 10 is what SAAMI uses, so there's no point in trying to be more precise than their baseline is).

Interestingly, your velocities are higher than the Hodgdon data would suggest they should be, but GRT predicts closer to what you have than to what Hodgdon has listed. Conversely, QuickLOAD predicts lower velocities than Hodgdon does. Taken together, this suggests the relative burn rate of the powder has become a bit quicker in recent years. In any event, a range of relative burn rates seem to have been out there and the powder models disagree substantially, with GRT having an energy content of 3900 J/g, vs. 3750 J/g for QL, and the progressivity rate being 0.9683 in GRT, and only 0.2476 in QL. It's like they were testing two different powders. In any event, for the lot of powder you have, I am more inclined to believe the GRT model because it matches the limited data you have better than QL does.

In general, when your gun, after allowing for barrel length difference, gets a lower velocity than the Hodgdon test gun did, it means your peak pressure is lower for the same charge weight of powder. When you get a higher velocity than they do after allowing for barrel length difference, you have higher peak pressure for the same charge weight of powder than they do. This latter condition would agree with what you are seeing by way of a sticky bolt lift. It seems the Hodgdon data is from a lower burn rate lot than you have. I would be adjust down to find a 10-shot average of 2704 fps with your load. Then shoot ten shots for confirmation.

This is just the sort of situation that is the reason we always start with bottom loads and work up, and we don't try to start in the middle somewhere. If you had started with Hodgdon's middle value of 59 grains, you'd have been putting overpressure wear on your gun from the git-go, so good job on not falling into that trap.
Click to expand...
I ran lots of models in GRT and did some measuring to make sure I was far enough off the lands and my gun has a bit of a short throat.

One other things to consider is some barrels are just faster than others.

I am finishing up testing with 178g eldx as well with the same powder, and I am getting velocities significantly higher than the Hornady manual predicted. for example

178g ELDX, test barrel 23.75in
H4350 max 55.3g, expected velocity 2650fps

My testing results, 21.5in barrel, 8 rounds fired at 15ft
H4350 54.3g (a full grain below published max) avg 2674fps, ES 36, SD12
H4350 53.9g avg 2655fps, es 38, SD 12
 
Shadow9mm said:
To do a load workup that I consider to be excellent it generally means going through a full 100 count box of bullets. But that is not always an option and you can still get more than serviceable results doing less. If you ask Hornady charge weight does not matter until you change a full grain in powder, and seating depth has no effect. Granted I have not done nearly as much testing as they have, but in my limited experience that is not the case.
Click to expand...

An excellent load is going to be a waste the way I shoot. 1moa ish at 150yd is plenty good enough. It is hit or miss of target of certain size 300yd and beyond. Ability to read the wind is way more important.

1% change in powder charge in the wrong spot can make noticeable difference. Around the good spot 5% is still good. Number of grains doesn't mean much to me. Percentage makes more sense.

-TL

Sent from my SM-N960U using Tapatalk
 
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