The plain answer, point by point. There are no analytics scripts or ad pixels anywhere on this site, including this page.
Everything you calculate (calibers, bullets, powders, charges, results) is processed and thrown away. Simulations run statelessly: the numbers go to the calculator, the answer comes back, and nothing about the calculation is stored in any database. There is no account system, no history table, no profile built from what you compute.
The only personal data is the email you type to start the trial. It is used to: (1) create your billing record at Stripe, the payment provider; (2) track your subscription status in our small entitlements database so the site knows to keep your charts unlocked; and (3) send transactional billing emails only — your receipt, a reminder a few days before the trial converts to a paid month, a notice if a payment fails, and a cancellation confirmation. No newsletters, no marketing, no selling, no sharing beyond the processors named here.
Card details are entered on Stripe's own checkout page. This site never sees, transmits, or stores card data. Cancelling or updating the card happens in the same Stripe-hosted portal.
One cookie, for access control: a short-lived signed token that tells the server your subscription is current so the paid results load. No tracking cookies, no third-party cookies. Your email is also remembered in your own browser's local storage for convenience and can be cleared any time.
Like any hosted app, the infrastructure keeps standard operational logs (request timing, error traces) used to keep the service running.
Questions about any of this: same address.