A while back, Bryan Litz did a comparison of his solver, JBM, and the one I wrote (link in my sig), but the post might have gotten nuked when the forum software was upgraded. As expected, they were all pretty darn close because we all use the point mass method. However, all three of us used a slightly different method of integration - I stepped through distance, Litz stepped through time, and JBM used a variable step algorithm. Nonetheless, the differences were pretty small.
FYI, I also use a distance step. I wonder if Bryan has switched do a distance step as well.. The distance method is so much easier when presenting results as you usually want results at a known distance as opposed to a known time. I just eliminates an extra step/extrapolation.
I have also written (though it's not available publicly because it's a garish hack at the moment) a point mass solver that uses arbitrary drag functions. I think it is the simplest, most direct method possible. You seem to have gone a step beyond and actually tested some bullets, so here's a question: Given that we often see deviation from the standard drag functions at high velocity and near mach 1, is there a new standard drag function out there that will be a good enough approximation to real bullets so that we don't need custom drag functions for each bullet? G7 already comes very close - is a custom drag function for each bullet overkill?
That is an excellent question and is the holy grail of ballisticians world-wide. Unfortunately I just don't think it is out there... at least as long as we are stuck with solving the equations of motion. I mean a lot of our LR bullets can be classified as G5 or G7 like in their profile, but even these two behave very differently in the trans/sub sonic region. Each projectile is designed differently and as such has its own signature, thus I am resolved to test each on that I use. I think maybe the answer is enough of us investigating these functions and publishing the results....
Out of curiosity, what numerical integration method are you using?
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