It really depends on what you want it for.
For precision reloading, I use an Excel spreadsheet with a template that I created. It helps me keep track of all my weights (brass, primer, bullets, powder) and measurements (neck thickness, neck diameter, headspace, brass length, OAL, concentricity, MV, etc), calculate differentials (prime case vs. prime case with powder) to check powder weights and calculate stats such as average, range, SDEV, max, min, N size) for each of the above variables. I also enter into the sheet results such as group MOA, Temp, humidity, Baro, altitude, scope elevation and windage.
The other nice thing about using Excel is how easy it is to expand and contract the sheet to accommodate the number of rounds you are dealing with on each session, plus you can put in text which describe the rationale for the shoot.
