Pressure Trace
Videos
Sharpe's 1937 handloading data for rifle and revolver use. Note the 244gr and 250gr lead bullet loads. Also note that for revolver use, pital powders are used.
I have added this page to help explain the 44-40 chamber pressures, pressure curves and other related items. I hope these videos will help explain historical pressures vs modern pressures.
Here I hope to compare;
Original Black Powder Pressures - Pressure curves between 13,500cup and 16,000cup
Original Smokeless Powder Pressures - Reported lower than black powder loads, maybe 13,000cup
SAAMI max pressures - 11,000psi/13,000cup
Modern Black Powder Pressures - As low as 7,000psi (<9,000cup) and as high as 8,500psi (<10,000cup)
Modern Smokeless Powder Pressures - Winchester factory loads 6,500psi (<8,000cup)
Buffalo Bore factory loads - Claims to be at or below 11,000psi/13,000cup but warns against use in old firearms, (tight chambers/small bores)
The Missing Links
It would appear that original black powder loads probably produced between 13,500psi and 16,000psi with an average of about 14,500psi @ 1,370fps. Advertised velocities at the time was 1,325fps. I found that as the balloon pockets decreased in volume, pressures and velocities decreased to modern 8,000psi and about 1,220fps.
Smokeless powder charges produced 1,300fps and less pressures but used the same powder from it's inception during 1895 well into the mid-1920's.
1917 data shows "service pressure average" for the 44-40 normal loads (Winchester 73') at 13,000cup and 44 W.H.V. loads (Winchester 92') at 18,000cup.
Data shows that early smokeless powder loads created less pressures than black powder loads. These smokeless powders at the time would be eventually referred to as "rifle powders", slower burning than the "pistol powders" like Bullseye and Unique from Laflin & Rand...of which most started out as shotgun powders.
Notwithstanding specific powders - 1930's handloading data still used pressures between 15,000cup for revolvers and 16,000cup for rifles and 33,000cup for strong action rifles like the Model 92' and Marlin 94 types.
44 Winchester High Velocity loads were advertised "Low Pressure" but generated 18,000cup @ 1,500fps in 1903, later increased to 1,564fps by 1925 and 1,570fps by 1938 and until inventories were exhausted (sold-Out) by 1945. The reason for the low pressure advertisement and velocity increases are unknown but dissected cartridges show lower charges over so many years and 19.6gr of the Sharpshooter powder yielded 18,450cup.
Testing of the early smokeless powders or even later Sharpshooter powders for comparisons yielded, as expected, the pressures advertised.
I did not test for comparison, and can only assume, that smokeless powders in "balloon pocket" cases caused higher pressures with some powders. (won't be able to test this theory with original smokeless powders).
Modern manufactures and some handloading data add 10% to 20% buffers in max pressure advertisements, possibly due to older and smaller bore size (.4225") .44 firearms as compared to modern .429" types.
BLACK POWDER
This video shows the pressure curves created with replicated vintage black powder loads and modern black powder loads.
All black powder loads used 40gr by weight and compressed between .17" to .25" with a powder compression die. Some cases such as modern Winchester and Remington brass may not be able to hold this much due to their lower h2o capacity (smaller inside area).
All cases are solid head cases, old case have semi-balloonhead pockets, modern cases do not.
Replicated vintage black powder loads used pre-1884 unheadstamped cases that have the largest inside balloon pockets available. They created the highest pressures and fastest velocities, as advertised during that timeframe. I believe this to be due to the amount of powder that is down beside and "beneath" the initial ignition of the powder...possibly creating a "boost". The more shallow the pocket, the less "boost" created.
WRA era headstamped cases have a more shallow balloon pocket and produced medium pressures and medium velocities, consistent with advertised ballistics of that timeframe.
Modern cases, such as Starline, have no balloon pocket and created the least pressures and slowest velocities.
Black Powder Pressure Test Overlays.xcf-1.0 (RGB color 8-bit gamma integer, GIMP built-in sRGB, 8 layers) 314x577 – GIMP 2022-06-04 13-30-11.mp4Reloder 7 - 200gr to 215gr Bullets
This video shows the pressure curves created with Reloder 7 powder with .4255" 200gr Winchester JSP bullets, Accurate Mold's my 43-208A design and John Kort's 43-215C. Both modified Lyman 427098 designs.
My preferred load is 26.5gr with the 214gr 43-214A, crimped to get 1,350fps. A hard crimp alone can increase the velocity to 1,400fps+ thus increasing pressures in excess of 13,000cup.
_Reloder 7 Loads Pressure Test Overlays.xcf-1.0 (RGB color 8-bit gamma integer, GIMP built-in sRGB, 6 layers) 314x577 – GIMP 2022-06-04 13-36-43.mp4UNIQUE
This video shows the pressure curves created with Unique powder. Examples are loaded from Lyman's 49th handloading manual as well as some custom loads.
Extreme care must be taken when loading this powder. An accidental double charge of 6gr could make for a bad day in some firearms.
Unique Loads Pressure Test Overlays.xcf-1.0 (RGB color 8-bit gamma integer, GIMP built-in sRGB, 7 layers) 314x577 – GIMP 2022-06-04 13-40-27.mp4TRAIL BOSS
This video shows the pressure curves created with the Trail Boss published max load of 6.4gr and a case capacity load of 9.3gr using an Acme Bullet Company "Magma" style 200gr hard cast bullet.
Trail Boss Pressure Test Overlays.xcf-1.0 (RGB color 8-bit gamma integer, GIMP built-in sRGB, 3 layers) 314x577 – GIMP 2022-06-04 13-38-02.mp42400 Powder
This video shows the pressure curves created with 2400 powder using mostly Lyman's published loads for both Weak Action and Strong Action rifles.
_2400 Pressure Test Overlays.xcf-1.0 (RGB color 8-bit gamma integer, GIMP built-in sRGB, 5 layers) 314x577 – GIMP 2022-06-04 13-19-26.mp4IMR4227
This video shows the pressure curves created with IMR4227 powder using mostly Lyman's published loads for both Weak Action and Strong Action rifles.
It has been reported that this powder is position sensitive. It is possible that a few of these test show such issues with the delayed powder burn after ignition. It should also be noted that it is very possible that shot buffer may actually increase chamber pressures.
IMR4227 Pressure Test Overlays.xcf-1.0 (RGB color 8-bit gamma integer, GIMP built-in sRGB, 7 layers) 314x577 – GIMP 2022-06-04 13-32-33.mp4230gr/240gr Bullets
This video shows the pressure curves created with several powders with 230gr/240gr bullets. Hercules and Aliant both published 23.5gr @ 1,290fps and remaining below 12,100cup. Lee also published the same load on their 44-40 three die set pamphlet. Extreme care must be taken when loading this powder. Not all 240gr lead bullets performed as published and the powder did not really like the Speer DCHP
240gr Load Pressure Test Overlays.xcf-1.0 (RGB color 8-bit gamma integer, GIMP built-in sRGB, 10 layers) 314x577 – GIMP 2022-06-04 13-27-47.mp4