Larry's black powder curve tests?

[KenH]

Hello all, remember back in Jan, 2021 there's a thread asking about BP curves. Nobody seems to have them, so Larry Gibson volunteered to do some tests, he's got the pressure equip :)

https://castboolits.gunloads.com/showthread.php?415876-Has-anyone-got-access-to-real-BP-pressure-curves

I had been watching the linked thread for when Larry completed the tests. But, it seems Larry Gibson posted the results in a new thread and I missed it. Larry and I both have searched for his posted thread and have not found it yet. Does anybody have a link to it? Perhaps tagged it as a "subscribed thread"?

I hope so, I'd sure LOVE to find it for the results.

Ken H>

[cwtebay]

Following

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[Savvy Jack]

I have a few I tested with the PressuretraceII, if he can't find his

[KenH]

While we're hoping to see Larry's results, your results would also add to the database. You can post in the thread, or you can send PM, or even better an email with the data in perhaps a spread sheet?

Thanks for chiming in.

[Savvy Jack]

I may have to explain a few things but here are two photos
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44-40 Tests

Notes:
The "noise" at the end of the scale is due to the 1 1/4" diameter barrel and the way I had the forward part of the barrel secured to the platform
The Black Powder loads were from using original pre-1884 Unheadstamped cases, original results showed Avg. 14,285psi
Original results for the 10gr Unique powder load was 14,007psi
Bullets are different for the two tests, I never did tests the same loads for such comparisons.
I sent Larry my PressuretraceII for him to use as needed for any future tests.

[KenH]

Thanks Bryan - those are interesting results. I find it amazing that Unique and BP curves are so similar. The BP are slightly more "gentle" with the rounded peaks vs the Unique, but still looks just fine. The sharper peak of Unique should upset the base of bullet best of all.

Amazing you're using those pre 1884 brass - just amazing to a simple old country boy like me :)

Ken H>

[Savvy Jack]

Thanks Bryan - those are interesting results. I find it amazing that Unique and BP curves are so similar. The BP are slightly more "gentle" with the rounded peaks vs the Unique, but still looks just fine. The sharper peak of Unique should upset the base of bullet best of all.

Amazing you're using those pre 1884 brass - just amazing to a simple old country boy like me :)

Ken H>

Unique was originally called a rifle powder. I really can not comment on this topic much and is why I have kept my mouth shut
IMR-4227 shows much smoother lines as well as sharper spike. I will post many more if I can tomorrow and let those that know duke it out with the results.
Jim over at RSI coached me through my tests and I really can't explain details, my ignorance is great in this field and his patients was outstanding. I probably drove him to drinking pretty heavy!

You will be surprised by the 2400 powder results as well

Introduced in 1900, Unique, 1935 Powder Can (for sake of safety, do note use this as modern load data please)
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Sharpe's 1937 load data for the 44-40

NOTE the 250gr bullet data


Revolver - 200gr JSP, 11.1gr, 1,100fps @ 15,000cup
Revolver - 205gr Lead, 10.9gr, 1,100fps @ 15,000cup
Revolver - 250gr Lead, 9.4gr, 965fps @ 15,000cup
Rifle - 200gr JSP, 11.3gr, 1,520fps @ 16,000 cup
Rifle - 200gr Lead, 11.3gr, 1,300fps @ 16,000cup


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[Larry Gibson]

I'll repost some here.

Do you want just the data or do you want the time/pressure traces also?

[KenH]

if possible I'd like to see the pressure curves with each fps. As much info as you can easily post.

Thank you,
Ken H>

[Savvy Jack]

What is interesting is the IMR-4227 loads

Test 23 is 20.5gr with a Speer 4425 200gr JHP
Test 70 is 22gr with a Speer 240gr DCHP

Typical results when using IMR-4227 with 240gr bullets compared to 200gr bullets.

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Test 36
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[Savvy Jack]

Here are BP loads using modern starline brass

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Original pre-1884 unheadstamped brass
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[Larry Gibson]

45-70 BP Time/Pressure Curves (Traces)

Before I post the Time/Pressure Curves (TPCs) let me briefly discuss/explain what we will see. Savvy Jack, in his posts, mentions the anomalies in the TCPs. What you see there is far more common than thought, not only with strain gauge measurements but with oscilloscopes and with piezo-transducer TPCs.

Ever wonder why you almost always, with any published pressure data, only see the “average” and almost never see any actual TPCs from that data? The answer is it would scare the public to death and no one would buy their products. We all like to think all measure TOCs are nice and smooth going up and coming down just like these;

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Well, I’m here to tell you that those types of TPCs do happen they are not all like those. Some are very, very jagged, ragged, uneven or what ever you want to call them. In particular, lower pressure load TPCs are subject to numerous irregularities based on the type of test firearm, the thickness of the barrel over the camber and the Time Of Rise (TOR and the peak psi generated. First time I tested some Winchester and Remington 38 SPL factory WC it though everything went haywire because the TPCs looked like the teeth on a course saw blade. I then tested some Winchester 158 gr LHP +P and got nice smooth TPCs. I am no longer surprised at the anomalies that can be seen. It’s why I always have some “reference” ammunition with me when testing to double check if necessary.

The appearance of “noise” in the TPCs can be generated by many things. Savvy Jack mentions what caused the noise in his TPCs. The chambering of a round, the action closing, barrel whip, burning of powder outside the muzzle, the firearm recoiling, etc. can all seemingly cause “noise” in the TCPs along with low pressure giving inconsistent “stretch” in the barrel steel over the chamber.

So, with that, please don’t get too exited by what the TPCs look like. It’s why the analyzing of the other pressure test data is important in comparison. I have included that test data with each TPC posted. I’m going to post here a menagerie of tests including smokeless and duplex loads along with BP loads.

First let’s take a look at some old original REM-UPC cartridges. The charge under the bullet was a compressed 70 gr charge of BP. The granules were smaller than Goex fffg BP. We see the average pressure was 22,000.

BTW; the black “tick mark” at the end of the TPC is muzzle exit.

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A load I developed years ago for hunting with my trapdoor target/sporter was with a commercial cast [Liberty bullets…no longer in business] bullet with a wide FP meplat of 20-1 alloy. I bought them “as cast” at .461 diameter and hand lubed them with my beeswax/olive oil lube. It is a duplex load [7 gr 4759/52 gr Goex Cartridge] and under that 405 gr bullet it generated an average pressure of 20,900 psi. As we see the accuracy at 100 yards was excellent. That test was done in 2011. The TPCs look a bit flatter but that was I hadn’t yet changed from a 2 millisecond time to a 4 milliseconds time.

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Another commercial cast bullet (Desperado Cast Bullets) of 415 gr cast of 20-1 alloy over 70 gr of Goex Cartridge. The average pressure was 19,100 psi.

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The Lee 405 HB over 70 gr of Goex Cartridge [my 1873 45-70 service rifle duplication load]. The average pressure was 17,500 psi.

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The Lee 405HB over 70 gr of Goex Superfine. Superfine was a transitional powder available between Dupont discontinuing and Goex using that trade name. Superfine has granuals smaller than those of current Goex ffffg powder. It also gives pressures in ffffg BP range. A previous test of 70 gr Superfine gave an average pressure of 24,600 psi. This is a duplex load with 7 gr 4759 under 54 gr Superfine gave an average pressure of 25,000.

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A duplex load under the 405HB bullet with 7 gr 4759 under 54 gr Goex Cartridge gave an average pressure of 20,400 psi. This is my most used M1873 service rifle 45-70 load. It is quite clean shooting and many, many rounds can be fired with little to no fouling. No wiping of the bore is needed and neither is a blow tube.

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My 45-55 Carbine load for use in my M1873 carbine (H&R) is also a duplex load using 5 gr 4759 under 49 gr Goex Cartridge with the 405HB bullet. The average pressure rans 17,700 psi.

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I plan to put a strain gauge on my H&R Officers Model which has thinner barrel steel over the chamber. Perhaps that will give me smoother TPCs(?). Also with Goex being out of business I will perhaps pick up some other brand of BP?

[Savvy Jack]

The one thing I did not like about the PressuretraceII is that when I reviewed the results for the second time, they changed. I did copy basic information from the first results and noted them. But when I got home and reviewed them again, the numbers changed. Thus the difference between my initial results and printed results. I asked Jim about this and he said it would do this. His explanation went over my head.

Not to get too far off the OP's question, I must explain further for a better understanding of my goal with the 44-40.

The bp vs smokeless power curve (the charts most have seen) is unknowingly only half understood by most...maybe the following will help.

I was already getting a lot of flack back then and even got banned from one forum for posting my results...thus I kept the rest to myself and just shared my notes.

I too used a "control" factory ammunition for my base. This was always an issue because I knew factory ammunition did not advertise actual results, but a reduced max by a safety percentage. I can touch on that later. I did use Buffalo Bore's 44-40 "Heavy" which is not heavy at all and replicate the 44-40's original loads and are advertised to fall under SAAMI max pressures. So be it, I set their loads to SAAMI recommended Max +300 (11,300psi [13,000cup]) and the 44-40 factory loads fell well below SAAMI max as expected, sometimes below 6,000psi for the cowboy low recoil loads. In the meantime, the black powder tests and reloading manual tests confirmed my suspicions as well as older 1930's handloading max pressures (15,000cup revolvers and 16,000cup for rifles), and all of my results are parallel to historical and modern data.

To keep a long story short, my problem was all data was listed as cup but SAAMI added psi not long ago for the 44-40. That and Buffalo Bore's new loads was my missing link (backed up by Lyman's Weak and Strong action load data) that I needed to conduct my tests.

My over-all results vs Historical and modern data

1930's Handloading Data
15,000 cup revolvers
16,000 cup rifles
22,000 cup Winchester High Velocity Loads (also factory data)

Buffalo Bore's 11,000psi (13,000cup)

Results: (overview)

(cup is approx)
14,000psi/<17,000cup = Black Powder Loads in Original pre-1884 Cases
11,300/<13,000cup = Buffalo Bore Factory Loads
8,953psi/<11,000cup = Same Black Powder Loads using Starline Brass
6,600psi/<10,000cup = Winchester Super-X Hunting Loads
<6,000psi/<10,000cup = MagTech Sporting Loads

My "written" Test Results can be found here: https://docs.google.com/spreadsheets/d/1cZyKKXVyHq9as9uFJiko5yReJ9a-ER32YsENTgJGJs4/edit#gid=156474702

Back in line with the OP, with all of these questions I had, I wanted to know as close to facts as I could. Not withstanding pressure curves, Historical Black Powder loads created more pressures than what folks may think with those old weak cartridge cases. Modern stronger cases reduces some pressures. Early Dupont No.2 (RIFLE POWDER) smokeless powders, as seen in pressure curve charts, created less pressures than black powder loads. Winchester used Dupont No.2 in the 44-40 until about 1924. Winchester used Sharpshooter powder in their 44-40 HV loads from 1903, and in all loads after about 1924. Sharpshooter was also a RIFLE POWDER....as well as 2400 and Unique!!!

Skipping a ton of extremely important information, we skip to pistol powders......
Aside from weak action rifles such as the Winchester 73', the revolver's "weak spot" is with the cylinder wall thickness, cylinder lock detent thickness and materials used. The rifles continued to use the less stressful slower burning rifle powders, however, these slower burning rifle powders were not always satisfactory for use in revolvers. The enemy was not necessarily the smokeless powders, but the smokeless pistol powders which were mainly shotgun powders.

Bullseye powder, introduced in 1898, was bad news when abused or incorrectly used in revolvers or in weak action rifles with full charges. So much so that the military asked for help. Back around 1909, the US Government's loading machines kept dropping an occasional "double charge" of Bullseye in their M1909 45 Colt loads. Most of the time they would blow the gun with the first shot. DuPont came up with a replacement powder called RSQ. One could fire six consecutive double charged 38 caliber loads before it got ugly. Being "rescued" by DuPont, Major K. K. V. Casey requested it be called "RSQ"......Resque! The powder was dropped two years later with the Model 1911.

Getting back on track, we have to divide "powders" into four "categories"; Pistol, mid-range rifle (44-40, 38-40), large bore rifle (45-70) and Exotic rifle (30-06 etc). Powders designed to directly replace black powder did not have higher pressures or pressure spikes. That was the problem of the faster burning pistol powders needed to replace the black powder pistol cartridges like the 45 Colt and 38's.

Dupont No.2 directly replaced black powder volume for volume, 40gr BP vs 17gr DP2 for the 44-40. A RIFLE CARTRIGE.

Referred to as the ".45 Springfield Smokeless" Sharpshooter, by Laflin & Rand in 1897, was designed to replace the 45-70's black powder loads. This powder went to Dupont in 1902 then Hercules by 1914 and was Winchester's powder in the 44-40 RIFLE until the early 1950's when eventually replaced by a ball powder.

When Colt chambered their SAA in 44-40 to mate with the Winchester 73', it was a blessing...but when the black powder replacement powders were discontinued, the 44-40 fell to the wayside of the pistol powders, one of the most iconic myths of all time was created...the 44-40 being a "pistol cartridge"!

I know this information sounds stupid, but it has a lot to do with the most black powder vs smokeless powder arguments of all time.

The BP vs Smokeless pressure curve debate is true, but only when replacing black powder with a particular smokeless powder needed for the same performance. This is why one cannot use a pistol powder to replicate black powder velocities with rifles chambered for the 44-40...and is why one will not achieve bets performance in revolvers using powders best used in rifles for the 44-40.

Many other powders result in less pressure and a slower power curve because they are loaded lighter than full BP loads in ORIGINAL BP CARTRIDGE CASES. This is why ANY PUBLISHED SMOKELESS POWDER LOAD by a reputable handloading publisher such as Lyman is good for any firearm in serviceable condition.

With that, below is some of my Reloder 7 data (together with the above Unique data) used with the 44-40 in comparison with the aforementioned black powder data. This should give you a good idea as to the pressure curve comparisons between BP, rifle smokeless and pistol smokeless.

I know many will disagree and that is okay, I shoot what I want to shoot and you keep shooting what you want to shoot and we will all get along!


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I guess I could go on but it's probably already a mute point.

[Mk42gunner]

Very interesting. I don't have a strong enough math/ scientific background, nor the experience with pressure testing to follow all of the info; but what I read made sense to me.

Thanks to Larry Gibson and Savvy Jack for doing the testing, and being willing to post and explain the results.

Robert

[Mal Paso]

Excellent read, should be at the top.

[Savvy Jack]

I thought I would touch on some other powders that sometimes come into question. 2400, along with IMR-4227, are referred to as Magnum powders and they scare the bageepers outta non-magnum folks. These powders are nothing more than slower burning rifle powders that work very well in large volume pistol cartridges like the 45 Colt, 44 Magnum and large volume, medium range black powder rifle cartridges like the 44-40 (for pistol use) when loaded hot enough to burn proficiently. These powders work great when loaded hot for use in strong action 44-40 riflesper Lyman's manual and reputable loaders like Taffin. This does not mean they can not be loaded lighter in some cartridges, refer to your handloading manual. Larry could probably give some insight for the 44 Magnum.

Below are examples using 2400 loads in the 44-40. Refer to your handloading manual for max loads. The following is for discussion purposes only.
Compare with the 44-40 google docs data: https://docs.google.com/spreadsheets/d/1cZyKKXVyHq9as9uFJiko5yReJ9a-ER32YsENTgJGJs4/edit#gid=2134817374


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Lyman's 49th Max Load for Group II rifles, 1,638fps @ 19,000cup
my results... 1,672fps @ 15,618psi which should be closer to 18,000cup
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We can compare those to the black powder loads below,
40gr by weight, compressed about .17" in original pre-1884 unheadstamped cases
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40gr of Goex FFFg by weight, compressed about .20" in vintage WRA cases
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40gr of Goex FFFg by weight, compressed about .23" in modern Remington RP cases
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[KenH]

Sorry I've been out of town with no access this week and just got home tonight.

Thank ya'll both for posting and sharing the results. It's gonna take me a while to digest all the info. This is just the type of info I was wanting. Reading 'n digesting over the next couple of days.

Ken H>

[cwtebay]

My goodness, this is a lot to chew on. I am looking forward to giving this a good mulling over and utilizing this data!
Thank you so much to those who took the time to contribute!!

Sent from my Pixel 5 using Tapatalk

[Tar Heel]

Y'all need to get a hobby. :-)

[KenH]

Y'all need to get a hobby. :-)

That's the problem - got too many hobbies, and just LOVE details 'n info on each.

[RyanJames170]

Some interesting data, I honestly figured they had made a smokeless powder that was pretty much spot on for a replacement for black powder, to bad they don’t make it anymore..