Everything listed here is free and open source software under the GPL3 license (with a few 3rd party libraries under 3-clause BSD). Enjoy.
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)