Derived from extensive testing by Hornady Manufacturing Company, this app includes reloading data for over 200 cartridges and 300 bullets. Under carefully controlled conditions using the components and test equipment specified, we report only data that proved safe in our research. Users have the ability to purchase data for individual cartridges, purchase the whole current edition of the handbook, or subscribe and receive the entire handbook plus more. Subscription provides access to all handbook data on your mobile device and real updates for all new data without waiting for the new handbook publication to be produced.