Back in the 1960's a ballistician named Homer Powley devised a slide rule for determining charge, the most efficient powder, and velocity for any centerfire cartridge. Of course, it is limited to the powders available at the time it was invented. However, I think all those powders are still available today, so, if you are using them, the computer can be quite useful. I found one for sale on ebay once, I think. However, I recently came across a website that is an electronic version of his old slide rule. You can find it here, http://kwk.us/powley.html.

Ed