Muzzleloader ballistic help

[sabotloader]

I am planning to shoot my CVA optima (26 inch barrel) tomorrow morning with some 420 grain No Excuses bullets over a Walters wad, 90 grains of 777 and RWS percussion caps. Does anybody have a program that will tell me about how fast they will come out of the barrel? I put the globe sight below on my gun, but have yet to shoot it. I am trying to decide what yardage to sight in the main cross hair.

This will give you an indication, although it is with a slightly heavier bullet.