Vicarious 44-40 Pressure Testing

[Larry Gibson]

Vicarious 44-40 Pressure Testing

Savvy Jack has done considerable pressure testing of the 44-40 cartridge in a special fixture. His work mainly revolved around testing Black Powder loads. While commendable Savvy’s tests did not answer several questions on loads Outpost75 proffered. Winter had also set which severely restricted Savvy’s ability to test loads. Even though I test pressures via the Oehler M43 PBL (Savvy Jack uses a Pressure Trace System) I do not have a 44-40 test barrel. However, I do have a 44 Magnum test barrel.

Based on Savvy Jack and Outpost75s exchange I wondered if there was a way to correlate pressures obtained in the 44 magnum cartridges to the 44-40 cartridge(?). I had measured the case capacity of both cartridges using RL7 powder and found the case capacity of the cartridges (both were W-W cases) was very close.

266142

I had read in the past that given equal loads the pressures in the 44-40 would be about 95% of those in the 44 Magnum. Thus I pondered to Outpost75 the following hypothesis;

“ …I’ve measured the capacities or W-W 44-40 and W-W 44 magnum cases every way from Sunday and found they have essentially the same capacity. So, if I pressure test loads in 44 magnum cases in the 44 Magnum test barrel might they not give comparable pressures or at least a useful correlation figure? “ It was decided through further discussion I would pressure test some of Outpost’s 44-40 loads and my own 44-40 loads in 44 Magnum cases. Then selected known pressure loads could be chronographed in the same OM Vaquero revolver with 7 ½” barrel using the original 44-40 cylinder and the 44 Magnum cylinder from my FTBH Ruger 44 magnum. The Ruger FTBH 44 Magnum cylinder fits, indexes and has the same barrel/cylinder gap as the original 44-40 cylinder.

266143266144

Thus, we theorized if the same load in the different cartridges in the same revolver gave essentially the same velocity [there is always be some variation to be expected though] then we could assume the pressure to be the same. If not, would the differences be consistent enough that we could deduce a correlation factor such as the “95%” figure previously mentioned?

With that in mind I received from Outpost75 test samples of two of his bullets to test; the 43-206H and the 43-230G, both from Accurate moulds. I supplied two bullets also; the Lee 429-200-RF and the Lee TL430-240-SWC which I most often use in the 44-40 cartridge. All the bullets were sized .430 and lubed with BAC. Those four cast bullets would cover the most used weight ranges used in the 44-40 cartridge.

266145

The testing would be conducted in two phases; phase one would be pressure testing the selected loads in the Contender 44 Magnum test barrel. Pressure data would be measured and processed via the Oehler M43 PBL. Phase two would be chronographing in the Ruger OM Vaquero via an Oehler M35P chronograph with the start screen at 10 yards from the muzzle in both 44-40 cases and 44 Magnum cases selected from the pressure tested loads using the two different cylinders. Some of the 44-40 loads would also be chronographed in the Chiappa M92 carbine just for the information.

All cases used in both pressure testing in the Contender test barrel, the Ruger OM Vaquero revolver and the Chiappi M92 44-40 carbine in cartridges of 44 SPL, 44-40 and 44 Magnum were W-W cases. They were sized and loaded in RCBS dies for both cartridges. WLP primers were used throughout. Each bullet was seated to the crimp groove and a light crimp applied just enough to prevent bullet set back in a tube magazine. The TL SWC was seated to and crimped in the front lube groove. No set back or bullet jump was encounter during testing in the revolver or M92 lever action.

The initial pressure testing of the selected loads would be done in my 44 Magnum Contender barrel;

266146

The line connected to the strain gauge (shown in the photo) is connected to the Oehler M43 PBL. The strain gauge is permanently affixed to the barrel located at the SAAMI recommended point of transducer location. Previous testing with “reference” ammunition [factory loads of known psi measurement] shows this gives very comparable psi measurement to piezo-transducer measurements. However, there is one thing we must understand when taking psi measurement with a strain gauge. It takes 7,000 + psi to fully obturate most brass cartridge cases to fully seal the chamber and to put stress on the chamber walls [this is why many low pressure loads have “sooty” cases because they do not fully obturate against the chamber walls]. Then, for the strain gauge to measure any “stress” on the barrel steel, it requires several thousand more psi to induce enough stress. Thus, the lowest psi I measured of any shot during the testing was 11,300 psi but since it was with the 44 SPL cartridge I decided to use the lowest measurement obtained in 44 Magnum cases during this test.

The lowest psi measurement during this test with the W-W 44 magnum cases was 13,300 psi. Ergo, I conclude that if any shot fired in W-W 44 Magnum cases does not register a psi measurement then the psi is less than 13,300 psi.

As an example; one of the loads Outpost asked to be tested was his favorite 44-40 load of the 43-230G bullet over 6.0 gr of Bullseye. He pondered if there was any real difference between older Hercules Bullseye and newer Alliant Bullseye. As I had been given an older square tin of Hercules Bullseye which was still sealed, I thought I might be able to answer that question. There was no date on the older tin of powder but it was obviously old…perhaps someone knows when Hercules stopped using those tins?

266147

I opened the tin of Bullseye and inspected the powder and found no sign of deterioration, so I loaded a 10 shot string of 6.0 gr of the Hercules Bullseye along with a like test string but with 6.0 gr of current Alliant Bullseye. Both under the 43-230G cast bullet.

Neither test string registered any psi measurement thus we can conclude the psi was less than 13,300. I did track the velocity of each test shot. The average for the Hercules Bullseye load was 965 fps with an ES of 27 fps. The average of the Alliant Bullseye load was 961 fps with an ES of 33 fps. Essentially, we can therefore conclude, the Hercules and Alliant Bullseye powders are basically identical in burn rate per gr of powder. This and other testing demonstrate little change in burn rate, if any at all, between older Hercules and current Alliant powders of the same kind.

Phase one testing results;

All test strings throughout testing (pressure and velocity) were 10 shot strings. The data from loads that were pressure tested in the Contender 44 magnum test barrel;

44 SPL; Outpost75 requested a pressure test of his 44 SPL load with the 43-206H (213 gr) loaded over 6.0 gr Bullseye. It proved to be an excellent load in terms of its internal ballistics and on target performance. Accuracy was excellent, velocity was very uniform with an SD of 11 fps and an ES or 35 fps. The average psi was 14,000 with an SD of 400 psi and an ES of 1,200 psi…..an excellent load.

Data from 44-40 duplication loads tested in 44 Magnum cases in the 44 Magnum Contender test barrel:

429-200-RF (200 gr) with 6.0 gr Bullseye; no pressure measurement thus psi less than 13,300.

429-200-RF with 7.5 gr Bullseye; the average psi measurement was 17,800.

43-206H (213 gr) with 6.0 gr Bullseye; no measurement thus psi less than 13,300.

TL430-240-SWC (242 gr) with 6.0 gr 700X (my Vaquero and M92 load); no psi measurement thus psi less than 13,300.

429-200-RF with 25 gr RL7; only one shot gave a psi measurement of 14,800. The other 9 shots were less than 13,300 psi.

43-206H with 25 gr RL7; the average psi measurement was 17,300.

43-230H (233 gr) with 25 gr RL7; the average psi measurement was 20,300.

TL430-240-SWC with 25 gr RL&; the average psi measurement was 24,400.

Phase two test results:

Six loads were selected to be loaded in both 44-40 and 44 Magnum cases for chronographing via the Oehler M35P using the Ruger OM Vaquero 7 ½” barrel revolver with both its original 44-40 cylinder and with the FTBH 44 magnum cylinder. I’ll also list the velocities chronographed with selected loads in the 44-40 Chiappa M92 carbine with 20” barrel.


Load………………………44-40 fps…44 Mag fps…M92 fps

429-200-RF/6.0 gr BE……..947……… 1016………..1188

43-206H/6.0 gr BE………...903…………970………..1121

43-230G/6.0 gr BE………...881…………937

TL430-240-SWC/6.0 gr 700X..858……...937………..1061

429-200-RF/25 gr RL7……1053………..1130…… ..1428

43-230G/25 gr RL7………..1071……….1163

TL430-240-SWC/25 gr RL7..1157…........1204……….1488

All loads in 44-40 cases gave less fps than the same load in 44 magnum cases in the same revolver. The average difference is the 44-40 produced, on average, 93.4% as much velocity in the 44-40 cases as the same load did in the 44 Magnum cases. That does seem to suggest that what I had read years back about the 44-40 producing 95% +/- as much psi as with the same load in a 44 Magnum case is correct. So, is there a correlation we can use to determine safe pressure 44-40 loads with pressure testing being done in the 44 Magnum pressure test barrel? It appears so. Since all was equal in the revolver except the chambering and since velocity is directly related to pressure [all other equal as was in this test] I think we can safely conclude a load that produces so much pressure in the 44 Magnum will only produce 93 – 95% of that pressure in the 44-40 cartridge.

Note; nothing in this test is meant to imply any 44 magnum level psi is safe in any 44-40 chambered firearm. This test is only inferring we can find safe 44-40 level psi’s by testing 44-40 level loads in the 44 magnum test barrel.

[onelight]

Thank you for posting your results , I don't load 44-40 but very interesting (who knows I might ) as always from you excellent job and great post.

[Outpost75]

Thanks Larry! Having measured and authoritative test data beats computerized guessing every time.

[Savvy Jack]

Great work Larry and much appreciated!

I don't have the exact dates handy at the moment but I actually started working with 44-40 high velocity loads in a 44 magnum frame revolver (using a 44-40 cylinder) around 2012 somewhat under the wing of John Kort. Trying to estimate a rifle's HV 100 yard impact velocity, I discovered that the velocity produced from a (magnum framed) revolver at the muzzle much replicates such shots. Once I finished those tests I wanted to continue the HV tests using clear ballistics gel to see how the bullets performed at 100 yard impact velocities.

In the meantime John Kort sent me several batches of various lead mix 44-40 Lyman 427098 bullets to test in the gel with 100 yard impact velocities with black powder. The results were astounding.

Also in the works, I wanted to somehow try and come up with a way to test pressures with modern 44-40 loads. Because of the CUP/PSI difference and not knowing a given factory pressure, the wait continued. I doubted my capabilities but by the time Buffalo Bore came out with the 44-40 "Heavy", I had what I needed. After nearly five years or so, I was able to get the Pressuretrace II module from Jim Ristow at RSI. Jim really took his time and walked me through the process. The other missing link I need was offered by SAAMI dated 2015....11,000psi was equal to 13,000cup for the 44-40. With Buffalo Bores "Heavy" and the 11,000psi.... I was well on my way! Buffalo Bore assured me that the 44-40 "Heavy" met SAAMI max pressure specs meaning the loads should be at or just below 11,000psi so I set the Pressuretrace to 11,300psi using Buffalo Bore as my control.

Since then I tested nearly 1,000 rounds of 44-40 loads, including some black powder loads, and all but two tests were consistent in over all pressures. I wanted to test more but me, computers and electrical gadgets just don't work well together. There is nothing like driving all the way to the range and then something not want to work. It was nearly always either the trace (computer) or the chronograph...lol

I have since sent the PT module to Larry and hopefully he can put it to good use. I think he would certainly be better off with a 44-40 TC barrel than what I am using but I will send him what I have when he is ready for it.

Before I finished John passed away. Outpost75 has been a great help to me as well. THANKS OUTPOST!

I hope these links work but below should be my tests results and my final basic comparison and "go-to" loads for the 44-40.

I also used the Quick Load program and there were way too many variations to be anywhere near accurate. QL used CIP, not even close to CUP nor PSI (Piezo).

Also, converting PSI to CUP is dangerous but since the 44-40 is a low pressure cartridge......


Regarding CUP ratings in manuals, while the correlation between CUP and psi is too poor for reliably converting one unit to the other over a range of chamberings, within a single chambering the conversion by the ratio of the CUP and psi maps within the SAAMI system is going to be close enough for practical work. That is, 11000 psi divided by 13000 CUP is 0.846 psi/CUP for the 44-40, so you can take the CUP numbers in the Lyman Manual and multiply them by 0.846 to get a reasonable expectation of psi. Conversely, dividing psi by that same number will come close to CUP." ~Uncklenick ......I think it can be safe to assume that 18,000psi is close to 22,000cup but is strictly a guess based off of psi test results compared to cup HV loads in Lyman's 49th manual.. https://sites.google.com/view/44winchester/handloading/pressure-testing

USE THE FOLLOWING AT YOUR OWN RISK is intended for discussion purposes only.

My "Go-To" Loads
https://drive.google.com/file/d/1u7y1GdcT8CD4Lo2QvnhjzS5PaHf4dBo1/view?usp=sharing

Test Results (note powder tabs at bottom of charts)
https://docs.google.com/spreadsheets/d/1cZyKKXVyHq9as9uFJiko5yReJ9a-ER32YsENTgJGJs4/edit#gid=651705900

John Kort
https://sites.google.com/view/44winchester/contributors/john-kort

[Texas by God]

As a 44-40 user and admirer- thank you all for your work. If I remember correctly, Hercules changed from the metal cans to cardboard containers in the mid 1970's.

Sent from my SAMSUNG-SM-G930A using Tapatalk

[rancher1913]

I really hate you guys, now I got to dig out my old 44-40 and try some loads, to many ideas and not enough time.

[Savvy Jack]

I wish I had thought to load minimum 44 Mag loads. I think there was one or two that were close but not close enough to be reliable on pressures comparisons. I think only the Reloder 7 loads.

I also wish I could have tested Bullseye loads.


I did want to make sure everyone understands my tests were based on SAAMI max pressure settings on a factory cartridge that produced 1,350fps. There are several things to compare from my tests results.

Bullet hardness, diameter and design plays a large factor in pressure results. Using Reloader 7 with 240gr bullets of different designs produced that largest deviation results. Smaller diameter bullets produced less pressure than larger diameter bullets with the same load and bullet. CCI300 primers produced less pressure in some high pressure tests than WLPs. I use CCI300 primers on all HV loads to help reduces pressures.

Pressures in firearms with "larger" chambers than the test barrel should a tad lower but not much.

Other variations can also change the actual pressures in your firearms. Bullet seating depth, hard crimps vs soft crimps, large diameter bullets in small bore dimensions...just to name a few.


Replicated black powder results

If the Buffalo Bore data is set too weak then the replicated black powder 14,000 psi, 12,000 psi and 10,000 psi loads would record higher pressures.

If the Buffalo Bore data is set too weak then the Lyman manual load results would record higher pressures.

If the Buffalo Bore data is set too high then the Winchester Super-X Factory load data would be even lower than 6,500psi and Winchester factory Cowboy Loads would not even register


Buffalo Bore set to 11,300psi.....no max load "cushion".

Smokeless Powder Results

Winchester Super-X factory load (1980's) pressures, two ten shot tests resulted in 6,600psi and 6,800psi giving a large max load cushion
Cowboy loads would not register

Magtech Cowboy Loads barely hit 6,000psi and too low for reliable readings.

Replicated BP loads hit 14,000psi with 1800's brass, 12,000psi with original early 1900's brass and between 9,000psi -10,000psi with modern brass

Various Lyman "12,000cup" normal loads came in between 9,000psi and 9,300psi respectively giving a max load "cushion".
Lyman's HV loads varied between 12,000psi and 18,000psi respectively, the majority allowing for a small "cushion".

18,000psi seams to be close to 22,000cup.

[dtknowles]

Larry, I read your article about this in "The Fowling Shot" thanks for the testing and writing that you do.

Jack, my thanks to you as well.

Tim

[rintinglen]

It's stuff like this on this sight that is so interesting. I personally have no use for the info, as I no longer reload 44-40, but I can only applaud the ingenuity that went into this test and file away the info on a just in case basis. Who knows, an 1873 might someday follow me home.

[cowboy4evr]

I am a real fan of of the 44-40 . I use the LEE 427-200 RN cast bullet in my Marlin 1894 , made in " 93 or 94 " . It has a groove diameter of .426 . I use 6.5 grs of Bullseye power . It has become my std load for that rifle . I wish I had a revolver to go with my rifle , I really enjoy the 44-40 that much . I'm still looking . Regards, Paul

[Savvy Jack]

I promise the next time I see Bullseye I will get some. Never have tried it.

Bullseye, since 1898. Even back in the 1930's, Sharp reported for 44-40 Revolvers -
200gr JSP, 6.7gr, 955fps @ 15,000cup
205gr Cast, 6.6gr, 935fps @ 15,000cup

Larry's results are right on target!

Larry-(44 Magnum)
429-200-RF (200 gr) with 6.0 gr Bullseye; no pressure measurement thus psi less than 13,300 psi
429-200-RF with 7.5 gr Bullseye; the average psi measurement was 17,800 psi. 18,612psi should be very close to 22,000cup for the 44-40

SAAMI max pressure for the 44-40 is 13,000cup or 11,000psi.

Alliant website shows a max load of 6.1gr @ 885fps for a revolver. My guess (there is a reason why I don't gamble) would be somewhere around 9,500psi if they are including a typical "cushion" which I assume they would be since this is listed under "cowboy loads".

With only a 1.5gr difference in Larry's data, there is not much room for error from low pressures to high pressures.

[Larry Gibson]

Certainly agree with Savvy Jack if one is loading 44-40s for original 1st gen Colt SAs and rifles listed in Lyman's Group I (Weaker Action) firearms SAAMI MAP should be adhered to for safe loads. Several are listed as tested.

However, in Lyman's Group 2 (strong actions) category Lyman lists 44-40 loads upwards of 21,900 CUP pressure. There are several loads I tested that fall under that pressure level. Obviously the M92 and Ruger OM Vaquero I used in the test fall within the "strong actions" category.

[Savvy Jack]

, in Lyman's Group 2 (strong actions) category Lyman lists 44-40 loads upwards of 21,900 CUP pressure. There are several loads I tested that fall under that pressure level. Obviously the M92 and Ruger OM Vaquero I used in the test fall within the "strong actions" category.

I don't have all of my data in front of me at the moment but here are the Lyman loads I tested for the 44-40 and the data recorded with the PressureTrace II. Maybe this can help with some comparrisons.

The 17,832psi Unique load should be pushing Lyman's 21,000cup if I recall correctly.
266218

I did not note Lyman's 49th pressures or velocity so I will add them here respectively.

8.5gr Unique - 981fps @ 13,300cup
16gr 2400 - 1,183fps @ 11,900cup
18.5gr IMR4227 - 1,212fps @ 11,600cup
---
---
---
10.2gr Unique - 1,282fps @ 19,600cup
20gr 2400 - 1,638fps @ 19,000cup
20.5gr IMR4227 - 1,455fps @ 19,700cup
10.5gr Unique - 1,410fps @ 19,700cup

[Larry Gibson]

Savvy, you've a memory like a bear trap.....[smilie=l:

[ndnchf]

Great info guys, thanks for all you did and sharing this.

[Savvy Jack]

Savvy, you've a memory like a bear trap.....[smilie=l:

LOL! Nope, I found my video on youtube and got the data from there.

Back when I was being accused of trying to make the 44-40 into a 44 Magnum.

Part 1 - https://www.youtube.com/watch?v=fJTuhN6doKw

Part 2 - https://www.youtube.com/watch?v=CT0FDPAhHf0

[Texas by God]

The 44-40 is no .44 Magnum!
It’s much better.;-)

[Savvy Jack]

The 44-40 is no .44 Magnum!
It’s much better.;-)

You just gave me PTSD! :mrgreen:

[yeahbub]

Larry, thanks much for having run the data, done the work and provided much food for thought. I had a friend who loaded for the .44-40 in a '92 and wanted to reproduce the "High-Speed" loadings, but with slower powders. We hadn't heard of the 95% idea, but I figured there had to be some relationship, going from a smaller to a larger case with identical loads. This was back in pre-internet days, and we always wondered how to safely borrow/modify .44 Mag loadings without being on thin ice. If I can find him, I'll send him a link to this thread.

[Ajohns]

Just curious, to be within the higher pressure limit, say 21,000cup in strong action class. Is H110 not a good powder to use because of? The amount of grains used would less than ideal for a good burn? Does anyone use H110 for 44wcf and have good results?

[Outpost75]

Just curious, to be within the higher pressure limit, say 21,000cup in strong action class. Is H110 not a good powder to use because of? The amount of grains used would less than ideal for a good burn? Does anyone use H110 for 44wcf and have good results?

In my experience H110 and W296 do not ignite well or give uniform ballistics at the lower pressures <13,000 psi required of the .44-40 in standard pressure loads, nor do they work acceptably at +P ~20,000 psi suitable for the post-1920 Colt New Service, Gen2 and Gen3 Colt SAAs, Ruger Vaquero, Winchester 1892 and Marlin 1894, because suitable charges leave excess free airspace in the case which results in poor ballistic uniformity.

For full-charge .44-40 rifle loads I found that H- or IMR4227 worked well and didn't suffer the erratic velocity issues I experienced with Alliant #2400, H110 and 296. RL7 and 4198 are also very good for rifle use.

[Ajohns]

That's kinda what I thought. Just wanted to ask from someone who would know. I enjoy this info very much, it's a great list for a great round.

In 44 wcf, what kind of charges are suitable for higher end speed using Imr 4198? I've heard RL 7 being used, I use 4198 a lot in 25/20 for higher end power in the M92.

[Savvy Jack]

In 44 wcf, what kind of charges are suitable for higher end speed using Imr 4198?

IMR-4198 gave me higher pressures than H-4198

Results are PSI not CUP

13,000cup max/11,000psi max

Winchester 73' 11,000psi MAX
Winchester 92' 18,000psi MAX (approx) [18,000psi should be close to 22,000cup with my results based on Lyman's 49th data]

26gr...IMR4198...200 RNFP...Laser Cast..............1,512fps....15,145psi

26gr......H4198...200 JHP..... XTP.......................1,247fps....11,641psi
26gr......H4198...200 LRNFP...Laser Cast Magma..1,380fps....11,707psi
27.5gr...H4198...200 LRNFP..Acme Magma..........1,424fps....13,387psi

MGM testing barrel 1:20" twist 100 Yards

266549


https://www.youtube.com/watch?v=6CiUFqhsFcg

https://www.youtube.com/watch?v=UN6undl4ZgI

https://www.youtube.com/watch?v=TfH0ETSpnIA

[Outpost75]

Brian, thanks for posting this. Some of my Rossi chronograph data:

.44-40 Winchester loads in Interarms-Rossi Puma with 20” barrel:

Ammunition___________________Vel@15ft, Sd, ES

Winchester 200 JSP factory load____1158 fps, 18 Sd, 51 ES

Handloads in Starline cases, with Remington 2-1/2 primers

Remington 200 JSP, 24.5 RL7_______1355 fps, 22 Sd, 74 ES

Hornady 200 XTP, 28 IMR4198______1642 fps, 20 Sd, 63 ES

Matts Bullets 215 LFN 28 IMR4198___1701 fps, 12 Sd, 41 ES

Matt’s Bullets 215 LFN 7.8 Red Dot___1273 fps, 15 Sd, 57 ES

Matts Bullets 215 LFN 35 Goex 3Fg___1172 fps, 28 Sd, 98 ES

Accurate 43-230G 7.2 Bullseye______1167 fps, 8 Sd, 25 ES

[Savvy Jack]

Great Report Outpost75

I wish I could have tested batches of original powders, the results I bet would be surprising!

1,830fps achieved with #1204 with a Winchester JSP (probably between .424" and .4255")

266570

[fcvan]

Cool thread. I don't load 44-40 and barely do 44 M, that's my Wife's gun, a SBH. Although she doesn't mind recoil I plan to load some 208 gr wad cutters at 1000 fps. I think it will be a good gallery load. I got the mold in trade from a member here, along with a 41 mold I had eyed but never bought. I do however load 38-40 for an OM Ruger Vaquero. I know the SBH frame of the OM can take loads equivalent to 41 M, I already have a M57 and a Marlin 1894 for that. Shooting BP equivalent loads with Unique or Bullseye will do for 38-40 for me.

[Trailrider SASS #896]

Howdy, Larry,
With Savvy Jack's assistance I've found this thread. I have not done pressure testing with .44-40 or .44 Magnum, but have done considerable testing of .45 LC using an Oehler M43PBL. I would be happy to send you copies of the data, as there is just too much to post here.
So far as case capacities of .44-40 and .44 Magnum are concerned, I measured the water capacities with a 212gr. bullet seated to the crimp groove. The water capacities were as follows:
.44 Magnum Remington 26.9 gr. H2O
.44-40 W-W 30.1
.44-40 Starline 28.9
Obviously there is considerable difference due to case wall thickness.

I determined that 8.0 gr of Hodgdon't Universal in the W-W .44-40 and 7.5 gr of Universal in the .44 Magnum with the same 212 gr bullets (commercially cast to 17-22 BHN) produced 950 ft/sec from a 7-1/2" Ruger Old Model Vaquero. The gun has interchangeable cylinders. I would comment that the .44-40 cylinder has .425" throats, with the bullets sized .430". This is my standard Cowboy Action load. I haven't been able to pressure test these loads as I really haven't wanted to mess up the finish on the cylinders when I cement the strain gages on them. I did do so with a .45 LC cylinder. I haven't done any testing for a while due to lack of a range with electrical power available, and the batteries in my very old laptop are not long enough in duration without 110v backup. :cry:

My objective in the .45LC testing was to determine, if possible, pressure spikes due to "premature shotstart", which theory suggests may have been responsible for overpressure destruction of some sixguns (as explained in my "Trailrider's Guide to Cowboy Action Shooting" (now out of print). Some of the results were also verified by Hodgdon's.

[Norske]

In reply to the question about the Bullseye powder metal can, my first pound of gunpowder was a can of Bullseye just like that one at a K-Mart store for $2.15 (the price tag is still on the can). That was in 1967. Almost every retailer of firearms sold reloading supplies back then.

[Savvy Jack]

How about 1927

268741

[Outpost75]

My hunting buddy who we will call "ER Doc" inherited a Colt SA "parts gun" in .44-40 which has the standard "plow handle" grip frame, but a 7-1/2" Bisley barrel with target sights, assembled on a black powder frame by King Gun Works in the 1920s. I'll try to get pictures of the gun.

Anyway, we shot the revolver with Accurate 43-206H cast 1 to 30 tin-lead from Roto Metals, sized .430" and lubed with LSStuff 45-45-10 and loaded with 6.5 grains of Winchester 452AA in new R-P factory primed cases. Most accurate .44-40 revolver I've ever shot. With 6:00 hold on NRA B-8 25-yard target using the old school Paine sights, 5 shots obliterated the X-ring. So, because Dennis doesn't load .44-40, we worked a trade and he bought a bunch of 1 to 30 ingots, gave me a caddy of 452AA, a brick of Remington 2-1/2 primers, and I found 500 new factory primed Remington cases on GunBroker.

He now has an M2A1 cal. .50 ammo can with 600 rounds of .44-40 ammo for his Colt and a newly acquired 1920 Spanish El Tigre levergun. He's all set for the zombies if they come to his neighborhood.

My late father always told me that friends are better than money and I know that to be true.

[Savvy Jack]

My late father always told me that friends are better than money and I know that to be true.

:2 drunk buddies:

[Larry Gibson]

Trailrider SASS #896

With Savvy Jack's assistance I've found this thread. I have not done pressure testing with .44-40 or .44 Magnum, but have done considerable testing of .45 LC using an Oehler M43PBL. I would be happy to send you copies of the data, as there is just too much to post here.

I would certainly like to have copies of your M43 printouts. I'll PM my address.

So far as case capacities of .44-40 and .44 Magnum are concerned, I measured the water capacities with a 212gr. bullet seated to the crimp groove. The water capacities were as follows:
.44 Magnum Remington 26.9 gr. H2O
.44-40 W-W 30.1
.44-40 Starline 28.9
Obviously there is considerable difference due to case wall thickness.

I determined that 8.0 gr of Hodgdon't Universal in the W-W .44-40 and 7.5 gr of Universal in the .44 Magnum with the same 212 gr bullets (commercially cast to 17-22 BHN) produced 950 ft/sec from a 7-1/2" Ruger Old Model Vaquero. The gun has interchangeable cylinders. I would comment that the .44-40 cylinder has .425" throats, with the bullets sized .430". This is my standard Cowboy Action load. I haven't been able to pressure test these loads as I really haven't wanted to mess up the finish on the cylinders when I cement the strain gages on them. I did do so with a .45 LC cylinder. I haven't done any testing for a while due to lack of a range with electrical power available, and the batteries in my very old laptop are not long enough in duration without 110v backup. :cry:

I do my pistol cartridge testing with Contender barrels for the same reason; just can't bring myself to mess up the finish on a cylinder...... Before the range got power I used a small generator to power the m43 and and my older lap top. wasn't much of a hassle but did add to the set up time. Now the range has power so it's a lot nicer. Have been waiting for the temps to drop a bit here as I've some testing to do.

I use W-W cases for both cartridges in my test and they gave very close to the reported 95% less psi in the 44-40 than the 44 Magnum. Your weights also indicate the psi difference would be in the 90 - 95% range difference also. My old Model Vaquero 44-40 cylinder has 429 throats (pin gauged) and the 44 magnum cylinder's throats run .430 - .4305 (pin gauged), guess I was lucky?

My objective in the .45LC testing was to determine, if possible, pressure spikes due to "premature shotstart", which theory suggests may have been responsible for overpressure destruction of some sixguns (as explained in my "Trailrider's Guide to Cowboy Action Shooting" (now out of print). Some of the results were also verified by Hodgdon's.

I'm not aware of what the "shot start" theory is?

[Savvy Jack]

269609

Which one is the 44 Magnum and why?

[Larry Gibson]

Saavy Jack

My first outing/test with the PT II wasn't productive due to operator error. I think I've got the problem solved and corrected my error as static testing shows all ok. Hopefully will test tomorrow.

[Savvy Jack]

Saavy Jack

My first outing/test with the PT II wasn't productive due to operator error. I think I've got the problem solved and corrected my error as static testing shows all ok. Hopefully will test tomorrow.

Awesome, I am nervous...shaking worse than a dog trying to crap peach seeds!!!

[ddixie884]

269609

Which one is the 44 Magnum and why?

I think it is the middle one. Because of the shape of the combustion chamber........

[Savvy Jack]

I think it is the middle one. Because of the shape of the combustion chamber........

:bigsmyl2:

That is correct, so tell me about the shape of the chamber.

[Larry Gibson]

Comparison Test; Pressure Trace II to Oehler M43 PBL

Yesterday, October 19, 2020 I conducted an extensive test comparing the pressure measurements of the Pressure Trace II (PT II) as compared to the Oehler m43 PBL. The test rifle was a M1909 Argentine M98 Mauser actioned rifle with a 24” 308W chambered barrel on it. The barrel twist is 1 in 10” and the chamber was cut to minimum SAAMI specifications with a match reamer. Two strain gauges were permanently affixed to the barrel over the chamber 180 degrees apart at the SAAMI specified location for a piezo-transducer gauge. Thus giving, hopefully, the ability to record the pressure data from each shot on both systems simultaneously with each shot.

One gauge was attached to the Oehler M43 and the other gauge was attached to the Pressure Trace II. Set up was a bit involved as two computers (laptops) were needed as the M43 runs on the Windows XP program and the PT II runs on Windows 10 program. The M43 connects direct from the M43 console to the laptop. The PT II blue tooths from the console to the laptop. Also the PT II does not have chronograph capability so an addition chronograph is need for velocity manual input into the program. Thus, to give a full spectrum of capability, I set up both sets of screens [muzzle and down range in front of the 100 yard target] for the M43.

The test was conducted at the Sara Park 100 yard rifle range. Temperature ran 75 – 85 degrees during the testing, Humidity was 20% with a barometric pressure of 29.92. There was little to no wind.

Calibration with “reference ammunition” and use of the correction factor (CF). In past conversations with Dr. Oehler he suggested using a percentage CF instead of the differential CF that SAAMI uses. The differential CF used by SAAMI is only useful in a narrow range of psi measurements for any test barrel whereas the percentage CF is useful over a wider spectrum of psi measurements. The measured psi is multiplied by .95 to get the probable psi.

Unfortunately, the PT II system uses the SAAMI differential CF method. The CF is easily changed in the PT II program, but the CF is not consistent given different levels of measured psi. For example, with the four full power 308W loads tested a CF of 12,000 psi was very close. With a subsequent test of low end cast bullet loads in the 11,000 to 20,000 psi range a CF of 2,500 to 3,000 psi would have been correct. In the 20,000 to 30,000 psi range a CF of 3,000 to 4,500 would have been correct. Using the 12,000 CF which was correct with the full power load would have doubled the psi of the 5 gr Bullseye load under a 150 gr cast bullet. As it was, 8 gr Bullseye under the 150 cast bullet ran 21,200 psi with the M43 and 17,758 psi with the PT II both without a CF correction.

I used four different .308W loads of known pressure +/-.

Two Federal factory loads were used as reference ammunition. I only had a few rounds of each (4 and 6) as this ammunition was used to initially “calibrate” the barrel and to check its measurement after some use. A factory technician had given me the factory psi measurement of those lots of ammunition. Thus, when test fired in the test rifle using the M43 a “correction factor” (“CF”) was easily computed. The CF for the test rifle is .95% and has remained consistent, given other variables, throughout the barrels use. Someone may mistakenly think this is not valid reference ammunition but if one reads the SAAMI manual, they will find the use of a lot of factory ammunition of known psi is valid if standard SAAMI reference ammunition is not available.

The first Federal factory reference ammunition I used was the Federal 308W Premium loaded with Sierra 165 gr SPBT Game King bullets. The cases were FC, the primers Federal 210 and they contained 47.3 gr of a ball powder. Factory measured psi was 59,200.

The second Federal factory reference ammunition I used was the Federal 308W Standard load with the 165 Sierra SPBT Game King bullet. The cases were FC, the primers Federal 210s and they contained 42.0 gr of a ball powder. Factory measured psi was 52, 100.

A Lyman [50th Edition Reloading Handbook] shows a maximum psi tested load using the 175 Sierra MK over 45.2 gr of Varget in Remington R-P case, with Remington 9 ½ primers with an OAL of 2.800” giving 59,300 psi. I was able to exactly duplicate that load. That load, in last week’s first test ran 62, 300 psi [M43] (CF) and there was some “hard” bolt lift. The Lyman velocity listed (24” test barrel) is 2708 fps and the M43 recorded a muzzle velocity of 2754 fps from my test rifle 24” barrel. That 46 fps increase in velocity plus the harder bolt lift indicate that load with the components I am using is about 1 + gr over max. For this test I reduced the load to 44.0 gr of Varget with all other components remaining the same. We see, with this example, we still must consider the variation of lot to lot tolerance stacking +/- of the variation in components I used vs those lots Lyman used.

A “standard” M118 match load using the 175 MK in LC Match or R-P cases, Winchester WLR primers with 41.5 gr IMR 4895 with an OAL of 2.825” is stated to run at 59,000 to 61,000 psi. I also duplicated that load for testing. Again, as always when comparing our own loads to published loads we still must consider the lot to lot tolerance stacking +/- of the variations of components I used vs those lots Lyman used.

With the Federal 308W Premium factory load I only had 5 rounds left and one did not pick up on the PT II [operator error] so only 4 shots recorded on both systems. Not as many as I’d like but still gives us an idea. The PT II psi with a 12,000 CF ran 59,621 psi and the M43 after the CF calculation ran 58,900 psi. Given the factory psi was supposed to be 59,200 psi both systems were quite close as expecting “spot on” is an unrealistic expectation given all the variables involved.

With the Federal 308W 165 SPBT standard load I had 6 rounds left and all rounds recorded on both systems. The PT II ran 53,748 psi (CF) and the M43 ran 51,500 psi (CF) both of which, again, are quite close to the factory psi of 52,100 psi.

The Lyman Reloading Manual load was reduced 1.3 gr of Varget to a charge of 44.0 gr with all other components as specified. That load ran 59,542 psi (CF) with the PT II and 59,700 psi (CF) with the M43. Bolt lift and extraction were as to be expected with a top end load. The muzzle velocity was 2709 fps. That is, again, quite close to the Lyman manual psi of 59,300 at 2708 fps.

An excellent example of why we should always work up a load and how beneficial the chronograph can be in that endeavor.

The last full powered load tested was a standard M118 duplication load with the Sierra 175 Match King bullet. By the time I got to this load I was getting the hang of operating the PT II system consistently and in conjunction with the M43 System. Thus, I was able to get the 10 shot test string to record simultaneously on both systems with each shot. The PT II measured the psi at 61,064 psi with a CF of 14,000. A second 6 shot string with the CF set at 12,000 gave a psi of 59,464 psi. The M43 gave a psi of 59,800 with a muzzle velocity of 2645 fps. That is where both the psi and velocity should be.

Here is the PT II data sheet;

269785

Here is the Oehler M43 PBL data sheet;

269786

Note the more complete data the M43 system provides. That is because the PT II system only measures the pressure. Any additional data is manually inputted such as load information (Note section) or velocities which must be gotten from a separate chronograph and inputted manually. The M43 PBL, as I have it set up, converts the average screened velocity to actual muzzle velocity The M43 can measure the time of flight to 100 yards or less and give the actual BC of each fired bullet. That measurement also is helpful in determining the stability of the bullet. There is also an external ballistic program to 500 yards which provides additional information. This is not to detract from the PT II but just is pointing out the differences.

The cost between the two systems is substantial and given the fact the M43 is no longer available adds to the attractiveness of the PT II system. Just be advised that if more than just psi is wanted then additional equipment and subsequent cost will be needed with the PT II system such as a chronograph and a laptop computer with Windows 10 on it that is blue tooth usable. Also, there is a learning curve with the PT II system just as there was with the M43 PBL system. Understanding what firearms the system can be used on and how the data is interpreted is essential along with a fundamental knowledge of internal ballistics. Neither system is for the casual reloader. One must be somewhat computer literate [more so than emailing and/or posting on forums] and have some ability working with equipment such as these as it can be frustrating to set up initially and to keep operational.

Additionally, some mechanical expertise is needed to properly glue the gauges on the test firearm. They are expensive and you will mess up one or two along the way. They also can detach or even break after use or miss handling.

I certainly am not trying to scare anyone off from getting a PT II or a M43, if one can be found, just pointing out it’s not a “run to the range and shoot” proposition. Planning for time and logistics of operation are essential as it’s not something you just run to the range on a whim to pop a few rounds with. If you have problems with setting up a chronograph at the range then neither system is probably going to suit you.

I am just beginning to learn about the PT II system and how to get valid information. Much more to learn for sure but I have several other comparative tests to run. For example, I think my next test with the 308W test rifle will be to attach both systems to the other strain gauge and test one of the same loads again. That should give an indication if the gauges are giving consistent measurements compared to each other.

Also, I am planning a test on my 44 magnum Contender test barrel. I will shoot a test (10 shots) of a known load with the M43 attached to the strain gauge. Then I will unsolder the wires of the M43 from the gauge and solder on the wires of the PT II and then shoot another 10 shot test of the same ammunition/load. That should also give a good indication if the PT II can be readily used on the other test barrels I have.

So much to learn, so little time……

[Savvy Jack]

Larry,

I can fully relate to and understand the time and effort it takes to perform such tests. I am extremely appreciative that you took the time needed to perform these tests. This is great and somewhat comforting!


https://sites.google.com/view/44winchester/contributors/larry-gibson/comparison-test-pressure-trace-ii-to-oehler-m43-pbl

[dangitgriff]

Larry—
Were the M43 and PTII certified for accuracy by an independent calibration laboratory before use? Without current calibration certs, your measurement data is only useful for relative comparative purposes, and not accuracy. In my field we use uncalibrated test equipment for indication only.
Another question I have is in using two different laptops with two different operating systems. Are both laptops equipped with the exact same processor? Different processor speeds could affect the data input rate recorded by the equipment and program used to log the data. That brings up another question as to the data transmission rate differences from the transducers to the laptops, which could incur further errors.
All this boils down to qualitative vs. quantitative results. There is also the safety factor, especially if you intend to push your testing into dangerous pressure territory.
All that said, your test results are informative and useful, and your attention to details laudable. A great job, in other words.
R/Griff

[Savvy Jack]

Without current calibration certs, your measurement data is only useful for relative comparative purposes, and not accuracy.

Of course not!


All that said, your test results are informative and useful, and your attention to details laudable. A great job, in other words.

Absolutely, this give us a reasonable estimate to compare factory loads with published handloads and with with components not published...and NOT NECESSARILY INTENDED to create our own Wildcats

[dangitgriff]

That is correct!
If using factory loads as a baseline for reference, all other measurements are perfectly acceptable as long as nothing else in the set-up is changed.
I sometimes have to remind my co-workers about this method. We use some high-end test equipment on occasion, with results submitted to the government.
Good luck, and have fun. Please post a pic of your test set-up if possible.
R/Griff

[Larry Gibson]

"Were the M43 and PTII certified for accuracy by an independent calibration laboratory before use? Without current calibration certs, your measurement data is only useful for relative comparative purposes, and not accuracy. In my field we use uncalibrated test equipment for indication only."

Yes, IF I had only used the raw data they would have been good only for "comparative" purposes. However........

Apparently you have not read the SAAMI manual on how pressure testing is actually done? If you had you would see, from reading my test results post, that I followed the same procedure testing with 2 different factory ammunitions and an exact duplicated load from Lyman's latest manual with a stated psi measurement. I've no idea what your field is but the measurement of psi in a chamber when a cartridge is fired is not exactly a precise measurement as compared to, say, measuring an object to .0001" with a micrometer. There we can "calibrate" the micrometer by actual adjustment. How do you know your powder scale is weighing accurately? You use "certified" weights to check. Were those weights "certified" by an independent laboratory? I doubt it. How do the ammunition manufacturers "calibrate" the pressure test guns they use either CUP, or more commonly now, piezo-transducer and also actual production firearms with strain gauges and Oehler M83s? They use "reference ammunition" of a specifically uniform lot of ammunition with a known pressure as per SAAMI Standards.

The use of the "reference ammunition" does not "calibrate" in the sense that the system is adjusted or corrected. Instead a correction factor (CF) [sometimes called an "offset figure"] is found by testing the "reference ammunition" in the test gun/barrel. The difference between the actual measurement of the instrumentation on the test gun/barrel and the known pressure of the "reference ammunition" is the CF/offset figure. That CF/offset figure is then used to adjust the measured reading "calibrating" it to a reasonably close pressure reading. And yes, even then the data is basically "comparative". That is why, for each cartridge, SAAMI lists 3 acceptable pressure figures; MAP, MPLM and MPSM. You might note in the data sheets posted there is a variation of velocity shot to shot and a variation of pressure shot to shot. We are not measuring exactly the same thing as each shot is different.

Both systems [the PT II and the Oehler m43 PBL] were checked by the manufacturers for accuracy and correct readings. The PT II was sent back to the manufacturer (RSI) last month to be checked out and was found functioning properly. The strain gauges are "certified and come with a "calibration" figure which is entered into the program of each system. Each system also runs a "check" and "calibration" of the system before each test. Then, as well noted in the test results posted, I used "reference ammunition" of known pressure to get a correction factor ("CF") for each system. The measured psi from each system was then "calibrated" using the CF to obtain a psi comparable to the factory or SAAMI psi's. That is how the ammunition manufacturers do it so "when in Rome, I do as the Romans do....."

If Federal says the pressure of the lot of their 165 Premium 308W ammunition is 59,200 psi and the CF psi figures for the PT II and the M43 PBL are 59,600 and 58,900 psi. Not exactly the same but then there is always an acceptable test to test variation which can be upwards of 4,000+ psi as per SAAMI standards for the 308W cartridge. Given the two systems over lapped the factory psi measurement by - 300 psi and + 400 psi I would say they are very close to giving a correct psi measurement according to SAAMI and industry standards. Probably a lot closer to actual psi than looking at primers, using a computer program, measuring case head expansion or guessing by felt recoil.....

[Savvy Jack]

Please post a pic of your test set-up if possible.
R/Griff

This is the PTII system I was using that Larry is now using
https://sites.google.com/view/44winchester/handloading/pressure-testing?authuser=0

If you guys ever get an interest in testing 44-40 loads, by all means I would love to see the results with those certified equipment and certified test ammo. Heck, I'd like to be there ;-)

[Larry Gibson]

Of course not!

Absolutely, this give us a reasonable estimate to compare factory loads with published handloads and with with components not published...and NOT NECESSARILY INTENDED to create our own Wildcats

Wildcats have indeed been created very successfully using the Oehler M43 PBL. Rick Jamison developed the Winchester WSM cartridges at his home in Oregon using the Oehler M43 with strain gauges on commercial barrels. He had custom reamers to chamber them made to his specifications. He then did load development measuring the psi and velocities with the M43. The results of his testing and development were used by Winchester to commercially introduce the WSM line of cartridges.

[Larry Gibson]

Here's a couple photos of the M43 PBL set up at the local range. It was bit more complicated with the PT II there along with another laptop but I forgot to take a picture of all that. Will do next test.....

269852

269853

[Savvy Jack]

Wildcats have indeed been created very successfully using the Oehler M43 PBL. Rick Jamison developed the Winchester WSM cartridges at his home in Oregon using the Oehler M43 with strain gauges on commercial barrels. He had custom reamers to chamber them made to his specifications. He then did load development measuring the psi and velocities with the M43. The results of his testing and development were used by Winchester to commercially introduce the WSM line of cartridges.

Oh thats sweet!!!

So you have the chronograph set up at 10 yards or so? I had mine about 10 feet. Is there a preferance?

[Larry Gibson]

The M43 PBL uses a 4' screen spacing both at the muzzle and with the down range screens. The proof screen is in the middle at 2' from the start and 2' in front of the stop screen. No real preference as with most such screens you want them far enough there is no chance of the muzzle blast giving a false start and you want the start screen to be a consistent distance from the muzzle with every test/set up. Thus with rifles I set the muzzle start screen 15' from the muzzle. With handguns I've been using 10' the last couple years. The down range screens are placed directly in front of the target. That information is then entered into the program as shown in the top left column of the data sheet.

[Savvy Jack]

the m43 pbl uses a 4' screen spacing both at the muzzle and with the down range screens. The proof screen is in the middle at 2' from the start and 2' in front of the stop screen. No real preference as with most such screens you want them far enough there is no chance of the muzzle blast giving a false start and you want the start screen to be a consistent distance from the muzzle with every test/set up. Thus with rifles i set the muzzle start screen 15' from the muzzle. With handguns i've been using 10' the last couple years. The down range screens are placed directly in front of the target. That information is then entered into the program as shown in the top left column of the data sheet.

thanks!!

[Larry Gibson]

The Rick Jamison saga is a sad one. He was one of the better gun writers back in the 80s and 90s. I always enjoyed his articles and have a couple of his books, one on coyote hunting/calling. He went to a lot of personal expense, development and time developing the short magnum concept. He was smart enough to patent the concept prior to approaching Ruger with the concept [the M77 was a favorite of his]. Ruger said they would make the rifles if he could get a major ammunition factory to make the ammunition. He approached Olin who agreed to make the ammunition. However, apparently Olin backed out of the deal as unless Jamison agreed to no royalties and only licensing Olin there would be no deal. That was atypical of the firearms industry who always thought they should get everything developed or invented for nothing. Ruger was the exception as they had agreed to royalties on every rifle chambered in a short magnum cartridge sold but they apparently got left out of the deal by Olin/Winchester also.

Within 1 year of the deal falling through Olin announced the WSM line of cartridges introducing the 300 WSM with Winchester [U.S. Repeating Arms] making the rifles. Jamison sued Olin and won. Unfortunately, the industry including the gun rags made Jamison persona non gratus so his writing career in the firearms field ended. Dr. Oehler was called as an expert witness to attest to validity and accuracy of the M43 PBL system Jamison used and his testing procedure. Apparently the industry was very displeased with his testimony he also almost ended up persona non gratus......

[Savvy Jack]

Apparently the industry was very displeased with his testimony he also almost ended up persona non gratus......

Yeap, I know exactly how he felt! You may not believe the push-back I get/got from most oldtimers that think they know it all when all they know is what they know. I was even forced out of one forum (member since 2007), accused of posting inappropriate data which actually came right out of Lyman's manual...go figure.

[dangitgriff]

Larry, I find this type of testing interesting. You’re speaking my language here. I am a systems/field/test engineer for a major DoD contractor. No, I haven’t delved into the SAAMI literature, but it is now on my radar. I have no doubt from reading your posts here you are checking all the boxes while conducting testing. The set-up is only as accurate as the least accurate/consistent component. The piezo pressure transducers you are using interest me as well. I suspect there are models that offer higher levels of accuracy but cost a lot more than the common man can afford. I think I might chase this rabbit a little further down the hole to satisfy my curiosity.
Meanwhile, please continue to update with findings. This is some good information.
R/Griff

[dtknowles]

My company and our customers require NIST traceable calibrations. That does not mean that our measurements are more accurate just that we can prove our accuracy.

Sometimes absolute accuracy is not required but the ability to identify trends. My Lee hardness tester does not provide absolute accuracy but it will tell me if one alloy is harder than another and about relatively how hard that alloy is.

If I had some calibration standards I could calibrate my Lee hardness tester or my Chrony chronograph. Larry is at least using some standards so I think his pressure measurements are quite accurate, maybe as accurate or more accurate than we see in published handbooks.

Tim

[dangitgriff]

Hey, dt—ever wonder how the cal lab calibrates their cal equipment? And how do they calibrate their calibration standards for the calibration equipment they use to calibrate the calibration lab equipment?
Ad infinitum... a bonafide universal mystery!
—Griff

[Savvy Jack]

Larry is at least using some standards so I think his pressure measurements are quite accurate, maybe as accurate or more accurate than we see in published handbooks.

Tim

This is what people are failing to look at. All most are doing is stopping right at the...."this is not done by pros, so it must not be correct". If I can do it, my lord, anyone with half a brain can do it. There are a few things that need to be consistent.

Not limited to...

1. Consistent handloads. I hand load all of my test cartridges one at a time. Powder dipping, trimming, weighing each load by hand etc. No loading presses. Now if you want to test the differences between your handloads and your press loads, that is always an option.

2. Having a good "control" such as a reliable factory load that you know is a certain psi. If the factory load you are using is 4,000psi (a low pressure cartridge) lower than max, then your results will follow suit.

3. If you input bad data, you will get back bad data

4. Conducting tests at the same basic temperatures. Testing at 32 degrees today and 95 degrees tomorrow might not be a good thing.

5. Making sure the equipment is working properly. Luckily for us, the PTII can be sent back to Jim for a quick check-up. Keeping a lap-top specifically for testing, not hooking it up to the internet, and not allowing updates. Doing what the user can do to keep the test equipment consistent.


I tested modern 44-40 factory cartridges against vintage replicated loads and against Lyman's handloads. Trying to best replicate actual components used. The best "control" I could find was Buffalo Bores "Heavy" that claimed to produce less than SAAMI map. Thus I set it at SAAMI MPLM.

My results are fairly consistent though not expected to be perfect. It was enough to fill in all the blanks I had.

269900
269901
269902

I know most folks don't like to click external links but here is the link to all 83 of my documented tests using the PTII that Larry now has.

(powder tabs at bottom of window)
https://docs.google.com/spreadsheets/d/1cZyKKXVyHq9as9uFJiko5yReJ9a-ER32YsENTgJGJs4/edit#gid=651705900

[Larry Gibson]

Hey, dt—ever wonder how the cal lab calibrates their cal equipment? And how do they calibrate their calibration standards for the calibration equipment they use to calibrate the calibration lab equipment?
Ad infinitum... a bonafide universal mystery!
—Griff

Also might note that at the Bureau of Weights and measures there is no "pound per square inch" of pressure to use or to "calibrate" firearm chamber pressure testing equipment to.

All methods of measuring chamber pressures are of a secondary measurement method [measuring the effect the pressure has on something else] and then computing/converting that effect into "psi".

[Larry Gibson]

This is what people are failing to look at. All most are doing is stopping right at the...."this is not done by pros, so it must not be correct". If I can do it, my lord, anyone with half a brain can do it. There are a few things that need to be consistent.

Not limited to...

1. Consistent handloads. I hand load all of my test cartridges one at a time. Powder dipping, trimming, weighing each load by hand etc. No loading presses. Now if you want to test the differences between your handloads and your press loads, that is always an option.

2. Having a good "control" such as a reliable factory load that you know is a certain psi. If the factory load you are using is 4,000psi (a low pressure cartridge) lower than max, then your results will follow suit.

3. If you input bad data, you will get back bad data

4. Conducting tests at the same basic temperatures. Testing at 32 degrees today and 95 degrees tomorrow might not be a good thing.

5. Making sure the equipment is working properly. Luckily for us, the PTII can be sent back to Jim for a quick check-up. Keeping a lap-top specifically for testing, not hooking it up to the internet, and not allowing updates. Doing what the user can do to keep the test equipment consistent.

There certainly are a lot of misconceptions regarding the ability to properly test firearms particularly as to calibration and testing in a "lab". Seems many, if not most, don't understand that factory and manual listed pressures apply only to the firearm or test gun they used. Those pressures are not necessarily what that same ammunition will generate in other firearms. Many, if not most, also believe all factory ammunition is loaded to the max safe level (the SAAMI MAP these days) and that all maximum listed loads in manuals are at that MAP level also. Those are false assumptions.

Many, if not most, believe/think all factory/manual pressure/velocity testing is done in a "lab". They aren't. Those tests are conducted on ranges. They may be indoor or out door ranges. Lyman used to do their testing on a 50 yard out door range. As Savvy mentioned, testing should be done at close to the same temperature but newer programs take the temperatures into consideration. Both the M43 PBL and the PT II require temperature, barometric pressure and humidity input. More importantly than the ambient temperature during the test is the ambient temperature of the ammunition. It is not difficult to control the ambient temperature of the ammunition even with the higher temperatures at the range when I test. The idea that a "lab" is needed is a false assumption.

As I and Savvy have mentioned numerous times both systems were tested at the manufacturer for accuracy. The gauges come with a "calibration" factor that is entered into the program and used for calculation. Also the use of reference ammunition is exactly what SAAMI does. Reference ammunition fired in Winchesters test gun will, no doubt, give a different pressure reading than the same ammunition fired in Remington's pressure gun or federals or anyone else's. That's why the "offset figure' or "correction factor" is used. It is a false assumption to think all the tests guns in all the different test facilities ("labs") will give the same pressure reading is a false assumption.

[faraim]

Gentlemen, Thank you so much for the great information. It's going to take me awhile to digest it all! The .44-40 is my favorite cartridge to reload and play with. Although I'll admit to a torrid affair with the .38-40 that I just can't shake! The Rick Jamison saga was a sad story, although I believe I've seen his work recently. I don't buy the gun mags anymore, sites like this are where the interesting info lies. Keep up the good work!