Range cards are very handy. Make them up for each rifle/cartridge pair you use in a scale you can read and plastic laminate them. Keep the cards with the rifle. Multiple cards can be made up for different air density where you may shoot. Keep it sensible for ranges and the information you need.
This is just an example of useful information on a range card with info you might want. Lots of other parameters can be included like bullet velocity and energy but it's mostly clutter for taking a shot. Many ballistic calculators provided more precise information, but they're much more expensive and slower to use.
This site has some range card calcualators which will print drop and wind cards for just about any rifle/cartridge/bullet combination. They're free to use.
JBM - Calculations