Added conversion from Joule to foot-pound and vice versa e.g. =bfx_u("ft-lb";3000) converts 3000 J to foot pound

Thanks Robert, I will update the add-in!
You have made it easy for me now to modify my Free Recoil spreadsheet to satisfy all shooters needs for different units.
When I was a kid in high school, Australia changed its unit system from imperial to metric and we all thought the world would change to SI units. Its a pity it never happened and probably never will.

Ian

Ian, would it be beneficial to include the Miller formula in BfX?
Robert

Robert, I think the Miller formula is fundamental to long range shooting. Anyone building a custom rifle needs to know what twist rate the barrel should have to stabilise the projectile that the chamber has been designed to use.

I think a BfX function for Miller's stability formula would be very much appreciated by all users. It would mean simple integration into a spreadsheet as another output (Sg) using a lot of the same input data for the ballistic functions already in common use.

Robert, if you have the time to implement a Miller stability function in BFX then please do it!

Ian

... I have first to study the subject a bit ...