Ballistics
Handloading, Pressure Spikes?
Due to the cost and primer availability, my testing and shooting has all but halted!
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Introduction
Before handloading for this great cartridge, the hand loader must understand several things.
Before handloading for this great cartridge, the hand loader must understand several things.
I am a firm believer that Starline Brass is by far superior than other brands for the 44-40. Starline's construction is between the thicker Remington brass and thinner Winchester brass, making it easier to handload but yet more apt to fit in any "finicky" chamber.
If you are only interested in Black Powder loads, follow John Kort's BP work by clicking here!
First; Bullets and Bores
Understand that a true 44-40 bullet has a diameter of .4255 (JSP) - .427 (Cast)
Understand that the WRACo. established [smokeless load] Service and Proof Pressures for the 44 cartridges by Feb 1917 which were;
For use in the Winchester 73', Service Pressure 13,000cup, Proof Pressure 16,500cup
For use in the Winchester 92', Service Pressure 18,000cup, Proof Pressure 23,500cup
Understand that older original pre-1900 rifles had bores as small as .4225" and should not use bullets with diameters greater than .427 pure lead...especially with loads that produce higher than modern SAAMI max pressures of 13,000cup/11,000psi (2015 SAAMI Standards)
Understand that most modern 44-40 firearms use 44 special/44 Magnum barrels with larger .429/.430 bores acceptable for using 44 Special and Magnum bullets with diameters of .429/.430 but "could" retain the smaller 44-40 case mouth dimensions making chambering difficult for thicker Remington brass using .429+ diameter bullets. Most retain 44-40 1:36" twist while some are reported to have the 44 Magnum 1:20" twist, suitable for long range 240gr loads.
Understand what a true 44-40 bullet "Profile" looks like. Certain so called 44-40 bullets and/or the use of some 44 Special and 44 Magnum profile bullets may be "too wide" just forward of the case mouth and touch the driving bands of the bore when chambered. This, along with simply adjusting the AOL, can increase chamber pressures and could cause problems in older "weaker" firearms.
Second; Strong Action vs Weak Action Firearms
Understand the difference between "Group I and Group II" rifles mentioned in Lyman's 49th handloading manual
Understand that the "thin" cylinder chamber walls in a revolver are certainly weaker than the thicker rifle barrel chambers and weaker than the "Action" on a Winchester 73'
Third; Desired Powders for Desired Results
Understand that when using rifles, longer distance shooting may yield better results when using slower burning rifle powders like Reloder 7, IMR-4227, 2400
Understand that when using revolvers, pistol powders like Unique and Bullseye yield better results
Fourth, Pressure Timeline
Understand that the following pressure chart may not be accurate but shows a plausible historic pressure timeline. Details and components are not shown. DO NOT use as load data.
Sharpe once wrote in his 1937 hand-loading manual...
" The 44-40 is capable of excellent performance when loaded properly for handgun use. If, however, one endeavors to combine loading for both handgun and rifle in this caliber, he is destined to meet with only mediocre success. As in all other dual-purpose cartridges, the factory loads are only a compromise at best. Smokeless-powder loading for handguns requires a much more rapid-burning type than loading for rifle use, as the short barrel must burn all the powder if satisfactory results are to be achieved. In addition, rifle cartridges can be loaded to a pressure of about 30,000 pounds in this caliber, whereas the same load in a revolver would be more or less disastrous."
Thus the reason for modern mediocre factory loads using pistol powders.
Did any English scholars out there notice the content that this was written? Although I am no scholar, this is written in a way that leads one to believe he is explaining that the 44-40 rifle loading has always been the lead role during that time-frame and that people were having issues with loading the revolvers, 100% reverse than is done today. Today, it is the revolver that is the lead role with pistol powders and the rifle loads that have mediocre success.
That wording meant that the rifle was king with rifle smokeless powders and the revolver needed help. Revolvers needed to use the new formulas of fast burning pistol powders to re-achieve their black powder performance.
So where is this "pressure spike" folks talk about when using fast burning pistol powders? Although seldom seen/shared correctly, it can and does happen. Even though it can happen, it typically is not seen until the loader tries to replicate 1,200fps or higher velocities. Once the loader starts to load these pistol powders for the higher performance, as Sharp mentioned in 1937, we can start to see such a spike. In the below chart, using faster burning pistol powder charges to replicate such velocities, we can see the pressure curve peak start to match those of the original black powder curves, but at much less velocities. However, what we also see is the faster ignition, faster climb and faster drop in pressures, which is a "pressure spike". The most obvious curve I replicated was done with a charge of WST powder....but that was about it!
I know what you are thinking...you are thinking....hey wait, there are three more curves that match or greater than WST. True, but...look at those velocities created.....and they were intended for the Winchester Model 92', not the Model 73' or Pistols. The near matching curve would be the 1963 Poof Loads. Interesting enough, even those loads have a bit shallower incline/decline in the curve than WST, and the velocities were closer to those of the High Velocity Sharpshooter load.
The mindset comes from the visual, but looking at the wrong curves. If we look at the curves created by modern black powder loads, then nearly all of those smokeless curves in the above chart, look disastrous compared to those black powder curves below. The following chart shows such modern black powder pressure curves for the 44-40.
The below chart shows all black powder loads 5 separate example curves. The nearly FLAT curves at the bottom are the same curves from the above chart, which are the modern black powder results using modern Starline cases.
When comparing the WST load to the other curves, they look very similar with the exception of the burn rate, sharpness of the curves themselves. Other than the sharpness of the curve and lack of a higher velocity, the WST loads fit right in with the W.R.A. Pre-1884 Unheadstamped cases (bottom red check) loaded with Goex FFFg.
Conclusion, where is the Pressure Spike?
In the chart to the right, Reloder 7 has less of a pressure curve that that of the replica 1873 black powder loads, but more than modern black powder loads...while WST may or may not have a pressure spike any different than that of the replica black powder loads. However, not the reduced velocity of the WST loads in comparison with the Reloder 7 loads.
Modern BP loads have virtually no pressure curve at such low pressures.
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