Black powder internal ballistics simulator

borbal

Well-Known Member
I don't suppose many (any) people outside of the USA hunt with black powder guns, but there are a goodly number of people both in the USA and in Europe who enjoy shooting historic black powder guns, or reproductions of them.

Creating a program that simulates the internal ballistics of black powder guns is difficult and it has been found very difficult to get accurate figures for the burning rates of black powder. Numerous experiments have been done over the years, but with little agreement. However, Don Miller (1996 Precision Shooting Annual) and Henning Umland both produced empirical equations fitted to practical results of muzzle velocity and muzzle energy which seem to work quite well. I then refined a burning rate for black powder to tune a full numerical internal ballistics simulator so that it closely agreed with these empirical equations, and here it is.

Both QL and GRT use the Don Miller equation for black powder simulations, but they do not give any pressure indications as the formulae only deal in muzzle velocity. My program is quite unique in that it does predict pressures.
 
Very interesting, thanks for sharing!
I’ll have to dig out my chronographed data when I get home but the calculator seems to be suggesting roughly what i remember in terms of velocity
 
Mine was using a 135 grain .45 round ball with Goex FFFg load of 80 grains distance was 70 metres and it ran 20 metres.
That is interesting.
What cal is your rifle
Most .45 patched ball rifles shoot a .440"-.445" ball of 127gns. Are you negating the patch?
 
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