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 [actually it is smokeless 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.

[see Savvy Jack's work here: https://sites.google.com/view/44winchester/handloading]

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. 

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. 

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 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?

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.

• [43-230G with 26.5gr RL-7; average psi measurement was 14,737 from Savvy's PTII results 44-40 20" barrel] 

• 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..............n/a

• 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..............n/a

• 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.