Before I load, I make a table in Excel which records the load info, cross referencing it against the shape of my cartridge box, and with space for me to record velocity, group size, and notes. I print it off and take it to the range (or take my laptop/tablet along), and take notes as I go. Once I find the load which works best, I highlight it in my excel workbook, and record it as "the load" for its respective firearm. I'll often take pictures of best groups, and can embed them directly into the Excel workbook.

If I find a load I REALLY like, it goes into a different Excel workbook of my "pet loads".

Sure beats keeping paper files or target records.