The reloading program I have requires muzzle velocity to figure out loads. How do I determine how much powder will give me a given velocity? Is there a program out there where you can put in the amount and type of powder you want to use?
You need to buy or borrow a chronograph to get an accurate number. It is possible, but not very easy, to use bullet drop from known distance to known distance and back out the velocity based upon the amount of drop that occurs.
There is a way to guesstimate your muzzle velocity.
At the back of most loading manuals, there are ballistics charts for each bullet. And these charts contain trajectory information.
So you zero the rifle at 100 yards. Then you shoot at 200 yards and at 300 yards. You measure the actual bullet drop at 200 and 300 yards and then compare the measured trajectory with the predicted trajectory on the chart.
And that way you can guesstimate the actual muzzle velocity.
I've tried this a number of times and when checking with the chronograph, this method will come within 75 fps or so.