A referee for
your handloads.
A local-first companion for precision handloaders. It predicts a load's velocity, pressure, and trajectory — then referees your range data with honest statistics. Referee, not cheerleader.
What it does
Two engines, kept deliberately separate: one predicts, one referees. Neither ever pretends to be the other. The science behind them →
Predict, never recommend
Model a load's velocity, pressure, and trajectory from its components. Every prediction carries an interval and a calibration grade, and pressure is shown only as a percentage of the SAAMI maximum — never a green "safe to shoot" light. It tells you what the physics says, and how sure it is.
Referee your range data
Feed it your chronograph strings and it answers the honest question: is this difference real, or is it noise? Confidence intervals on mean and spread, Welch's t, and a proper comparison of standard deviations — the statistics that tell you whether a load actually changed, instead of flattering a small sample.
Serious external ballistics
A full point-mass solver with spin drift, aerodynamic jump, and Coriolis; G1/G7 drag or your own custom drag curve; density altitude and wind. Read your come-ups as clicks on your scope's turret, true the model to the dope you actually shot, and get a one-tap firing solution: enter the range, get the elevation and windage to dial.
Yours, on every device
Everything lives in a local database on your machine. Sync it to your phone or another computer over your own network or a shared folder — no account, no cloud, no server in the middle. Export the whole book to an open format any time.
Find a load for a velocity
Work the model backwards: enter a cartridge, a bullet, and a velocity you want, and it surveys the powder-and-charge candidates that could reach it. Candidates, never recommendations — matching a velocity says nothing about how a load will group, so each carries its own interval, pressure as a percentage of the SAAMI maximum, and a calibration grade, ranked by model confidence, not by a precision it cannot know. Develop several loads under one ammo and compare predicted against measured, side by side.
On the command line, too
vlb is a headless, scriptable view of the same loadbook — survey candidates, predict a load, list your data, and log a chronograph string from the terminal or a script. Every --json output is a stable shape you can pipe to jq, and it shares the app's live file safely. Same referee stance: it never recommends, and it stores your raw velocities exactly as measured.
A look inside
The desktop flagship (macOS) and the field instrument (iOS) share one honest engine.
Screenshots are from the English build — the app is also available in Ukrainian.
A tool, not load data. Vegan's Loadbook is a simulation and a statistics instrument — it is not a substitute for published load data or your own judgment. Always cross-check against manufacturers' data, work up carefully, and treat its numbers as models to be verified on paper and steel. Safe handloading is your responsibility.
Get the beta
Native on the desktop, a field instrument in your pocket — the same honest engine underneath. Free while it's in beta.
Access is by approval, and it's geographically limited. The beta is opening first in the USA and Ukraine, distributed only to people we authorize by email — there's no open download. Eligible use is limited to Ukraine, the USA, and NATO countries.
Why: this is precision-ballistics software, and we won't make it available where it could be turned against Ukraine. See who can use it and the license.
Email-gated downloads are being set up. In the meantime, read the manual and the science.