I have a Lyman 44th edition Reloading Handbook, open to page 80, because I am reloading for .32-40. (Another question, feel free to answer, but not my MAIN question, is why is .32-40 not in the 49th edition, as it is far more common than .38-55, or .40-65, or several other rounds that ARE published in that edition??? Should have .40-65, .38-55, AND several others, in addition to, and not instead of .32-40, IMHO).
In any event, what exactly determines the maximum grains, other than the obvious--e.g., too much pressure, causing catastrophic destruction of the firearm? What I mean is, I loaded 16 grains of IMR 4227 behind a 170 grain Jacketed bullet, and it was very MILD when it came to recoil, there were no signs of excess pressure, etc. The maximum load for IMR 4227 is 16.5 grains, with a velocity of 1348 FPS. And yet, one could load 30 grains of IMR 4895, which yields a velocity of 1892 FPS, this being 544 FPS more than the maximum load listed using IMR 4227 powder.
So, what exactly determines this? I am NOT one to play with fire and use loads that are NOT published data, plus 16 grains of IMR 4227 in this Winchester 1894 carbine provides satisfactory accuracy. However, if I had to 'guess' it has something to do with IMR 4227 being much finer than IMR 4895, therefore, burning faster, and generating higher pressures. Am I correct here?
Is there a mathematical formula that determines all this?
In any event, what exactly determines the maximum grains, other than the obvious--e.g., too much pressure, causing catastrophic destruction of the firearm? What I mean is, I loaded 16 grains of IMR 4227 behind a 170 grain Jacketed bullet, and it was very MILD when it came to recoil, there were no signs of excess pressure, etc. The maximum load for IMR 4227 is 16.5 grains, with a velocity of 1348 FPS. And yet, one could load 30 grains of IMR 4895, which yields a velocity of 1892 FPS, this being 544 FPS more than the maximum load listed using IMR 4227 powder.
So, what exactly determines this? I am NOT one to play with fire and use loads that are NOT published data, plus 16 grains of IMR 4227 in this Winchester 1894 carbine provides satisfactory accuracy. However, if I had to 'guess' it has something to do with IMR 4227 being much finer than IMR 4895, therefore, burning faster, and generating higher pressures. Am I correct here?
Is there a mathematical formula that determines all this?