Gordon’s Reloading Tool Is Gone: What It Did, and What to Do Now

Update, 5 August 2026: Gordon’s Reloading Tool is no longer available. The project’s own site states that development has stopped and that, for security reasons, the GRT download has been removed — dated 27 July 2026. So this is no longer a live choice between two tools. The rest of this page is kept because the distinction it draws still matters, and because a lot of shooters are looking right now for what GRT did.

What GRT was

Gordon’s Reloading Tool was a free interior-ballistics simulator. You entered your cartridge, bullet, powder and charge, and it modelled the burn — projecting a pressure curve and a muzzle velocity. Its stated purpose was safety as much as performance: to help handloaders understand where a load sits relative to pressure limits before that load exists in a case. It had a deep component database, it was community-maintained, and it cost nothing.

For working out sensible starting charges, sanity-checking a wildcat, or understanding why a powder behaves the way it does in a particular case, it was an excellent and genuinely respected tool, and it was given away free for years.

What GRT never did

• It was a model, not a measurement. A simulation predicts what a load should do in an idealized barrel. Your barrel, your brass, your lot of powder and the temperature that morning will all disagree with it to some degree. That gap is the entire reason you chronograph.
• It never scored a ladder. Once you had shot ten charges over a chronograph, GRT was not the tool that read those ten strings and told you which charge to keep.
• It never touched your target. Group size, mean radius, vertical spread — the numbers that decide between two loads that chronograph identically — are outside its scope entirely.
• It never ran natively on a Mac. GRT was a Windows program with a Linux build, so Mac shooters needed CrossOver, Parallels, a virtual machine or WINE — for years one of the most-asked questions about it on the shooting forums. That is moot now that the download is gone.

What Loadscope does with the other half

Loadscope starts where GRT stops — at the moment you come back from the range with real data. It imports your chronograph sessions directly (Garmin Xero over the cable, LabRadar, MagnetoSpeed, Athlon), measures your target groups from a photograph, and then scores every charge and seating depth you fired on four measures at once: velocity flat-spot, velocity SD, mean radius and vertical spread. It names your best load, tells you how firmly to hold that call given how many shots you fired, predicts your dope, and prints a DOPE card. It runs natively on Mac and Windows.

How the two used to pair — and what to do now

1. Start from published load data. This is the step GRT used to help with. With it gone, a current published manual from your powder or bullet maker is the starting point — and it always should have been the final word anyway, since a simulation was never load data.
2. Shoot the ladder. Load a spread across that range, chronograph every string, and shoot each charge at a target you keep. How to run and read a powder ladder →
3. Finish in Loadscope. Import the velocities and the targets, and let the scoring name the charge and seating depth that actually performed — then print the range card for it.

Prediction narrowed the search; measurement settles it. With the prediction half no longer available, the measured half matters more, not less — what you actually shot over a chronograph and put on paper is now the only evidence you have.