Interesting Calculator

[Blain Crighton]

I dont have a Chrono to test this myself but others have reported it is good for  giving a general estimate of what to expect;
a fair good set of formluae

http://dragonflybridge.com/cgi-bin/MuzzleVelocity/Cartridge.pl

Has a link for patched round ball as well

Your actual mileage may vary