I love these mathematical formulas. What is the basis for the math? As one with a little math background I question them as the basis is kind of tenuous. A good load is dependent upon too many variables. Another good starting point with, less hassle is to use 1/2 the ball weight for a powder charge which would be about 12 grains for a 25. Some like to use the caliber in grains, (a 25 would then be 25 grains, a 50, 50 grains). These rules of thumb or formulas work best within a small range of calibers, but are limited for the extremes. There is one somewhere if I look it up that gives the best barrel length compared to bore diameter (I believe it is for shotguns). Taylor's stopping power formulas are another set of rather tedious math that favors large bores. They are likely workable as large bores are very effective.

DP