I use a spreadsheet. I use different tabs for different cartridges. I record the bullet, number of rounds, powder & charge, primer, brass, seating depth, date loaded, date fired and temperature, velocity average for each charge, extreme velocity spread, and group size. The beauty of it is that I can easily sort data to see what loads have turned in the best accuracy over long periods of time, since I've done it this way since about 2005. Example:

Code
Hornady 154-grain SP	     3	56.5 / H4831	Fed 210M	-0.030	01/06/08	01/15/08		1.70"
	                     3	57.0 / H4831	Fed 210M	-0.030	01/06/08	01/15/08		1.12"
	                     3	57.5 / H4831	Fed 210M	-0.030	01/06/08	01/15/08		.50"
	                     3	58.0 / H4831	Fed 210M	-0.030	01/06/08	01/15/08		.83
                             3	58.5 / H4831	Fed 210M	-0.030	01/06/08	01/15/08		1.75"



(I didn't record velocities when I tested this load.)

Don't be the darkness.

America will perish while those who should be standing guard are satisfying their lusts.