I certainly have tables of muzzle energy, using simple formulae based on velocity and weight of bullet, but there are so many variables in shooting BP firearms that it makes the use of charge weights as a method of calculating velocities unuseable.

Barrel length is also a factor here, as is the type of firearm used.

A Brown Bess using a maximum of 120gr of FFg will certainly 'ring gongs' at the shorter ranges, but as has been pointed out, downrange it's a different story, although at 50m it is not going to make much difference. Our 50m range, for instance, permits the use of LEAD projectiles up to and including .75cal to be shot, providing that they do not exceed 1500 fps. No Brown Bess on earth is going to match a 12g Brenneke slug either for velocity or m/e, and that is permitted on our range.

To get 1500 fps out of a Black Bess you are going to use an improbably high load - always supposing that such a load would actually be burnt in the barrel.

No BP handgun on earth is going to make 1500 fps - the usual limit of velocity, but letting us know the calibre will let us figure out the m/e, too.

A lot more information is needed from the OP before I could try and offer any meaningful advice.

So, OP, come back to me with the following details, and I just might be able to help you.

1. Type of firearm[s] proposed.

2. Current restrictions on YOUR range.

To get you started, here is an easy-to-use m/e calculator - just fill out the blanks -

http://www.americanairrifle.com/convert.htm

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