I use the graphing function in Excel.
It is easy, too. Once I set up the graph the first time, I just reuse the same file under a new name for each new load. The graph is automatically made as I type in the data.
By graphing the results, I can fit all the results of a particular bullet/powder combination, from an initial rough powder test to final fine-tuning of charge weight and seating depth, on one sheet of notebook paper. Plus, I've got a good record of what didn't work, as well.
Probably overkill for most folks, but I find it useful to keep track of what I have tried, and to spot hidden trends with a particular rifle.
