Talking ballistics for individual rounds is a whole thread in and of itself. If you at least know the velocity, bullet type, and bullet weight you can plug the data in here to get a decent idea: http://www.jbmballistics.com/cgi-bin/jbmtraj-5.1.cgi
As a general rule, you want the bullet to be super sonic (Mach 1.0+) at the distance you want to shoot.
Originally Posted by jimmykan
I bought a bunch of 142 SMKs from Henry!
Nice! I have been shooting 123 SMKs, but I am giving 142s and RL17 a try here soon...