Everything listed here is free and open source software. Enjoy.
It all moved: geladen.ch ballistics
Everything on this page now lives in one app. Trajectory gives you drop, windage, velocity and time of flight at any distance, with a full 4DOF Modified Point Mass engine underneath when you ask for it. Hit Probability works against real targets with real scoring zones, accounting for wind, range-estimation error and your own dispersion. The Range Solver shows two big numbers, readable in direct sunlight, and deliberately nothing else. BC Tools back out a BC from measured velocity or time of flight, convert between models, and read it straight off Labradar tracks. The Cd–Mach Curve builder derives your bullet’s own drag curve from your own velocity table instead of assuming a G1/G7 shape. And the Rifle Precision Calculator tells you what your rifle actually does, measured from a phone photo of your targets and a ruler, pooled across every group you have the courage to shoot.
Plus your own rifles and bullets, five languages, and a manual that explains things. It runs entirely in your browser, installs as a real app on Android, iPhone and desktop, works offline, costs nothing and always will, and collects absolutely no data — there is no server for it to be collected on.
Everything else on this page is legacy, and stays here only because I don’t break other people’s bookmarks. Plan 33 is now Trajectory and Hit Probability; TARAN is the Rifle Precision Calculator; Labrabaco is BC Tools and the Cd–Mach curve builder. All three picked up better math, honest units and rendering that isn’t from 2009 on the way over. The old pages still work — they just don’t get fixed, improved, or thought about any more. If you landed here from a ten-year-old forum post: the link you want is at the top.
Legacy tools, kept available for historical reasons
Plan 33
https://bc.geladen.ch/plan33/plan33.html
This is an external ballistics engine, which (yet another…) calculates trajectories for different rifles+bullets in different atmospheric conditions. But this functionality is collateral damage. The main purpose of the tool is to calculate the probability to hit a given target at a given distance in given conditions, as a function of various factors affecting the shooter and the bullet — say bonjour to reality (spoiler: in long-range shooting, the rifle’s own precision and the smallest group at 100 m is by far not the most important factor).
Development is ongoing. To come: full-auto hit probability, as well as automatic generation of über-precise ballistic cards for your, dear reader, own rifle and cartiridge.
TARAN
TARAN Target Analysis and Rifle Precision is a piece of software to determine shooting precision, by aggregating shot information from multiple targets and groups.
Hosted: https://bc.geladen.ch/taran/taran.html
User manual: https://geladen.ch/en/taran-user-manual/
Download: https://geladen.ch/en/taran-download/
Achtung: TARAN was my very first experiment with DOM/CSS (which dom/css I cordially hate since then) and JavaScript. The code is bleeding-eyes butt-ugly spaghetti, even by my rather loose programming standards. You have been warned.
Labrabaco
https://bc.geladen.ch/labrabaco/labrabaco.html
This is a prototype, which is supposed to calculate bullets’ ballistic coefficients from measures taken by Labradar devices. Yes, it is probably possible. No, I don’t know yet how precise it is (or isn’t). More news on this point to come real soon.
Complete source code archive: https://geladen.ch/wp-content/uploads/2023/04/labrabaco-2021-11-25-v.0.8.zip
(so that you don’t have to extract it from the browser cache)