Your Garmin Xero Records It. What Picks the Charge?

The Garmin Xero records every shot's speed and hands you an average, SD and extreme spread for each session. Picking the charge is a different job. It takes comparing sessions against each other and against your groups. Here's what that job involves, whether you build it yourself or let software do it.

What the Xero gives you

One session per string: every shot's velocity, the average, the SD and the extreme spread, plus the time it was fired. The unit holds up to 50 sessions, and the USB cable brings them all off at once. (How to get data off a Garmin Xero)

What a session doesn't carry is which charge it was. And the Xero never sees your target.

Four jobs stand between your sessions and a charge

1. Match each session to its charge. The Xero timestamps every session, so the order you fired them is already in the data. Shoot your ladder in order, one session per charge, and the first full session is your first charge, the second is your second, and so on. No naming sessions on the unit, no typing charges into your phone.
2. Set aside what isn't the ladder. A range day usually holds more than the ladder: a fouler, a cold-bore check, a string from another rifle. A fouler shows up as a session much shorter than the rest, and it needs to come out before anything is compared.
3. Compare charges to each other, not one at a time. SD tells you how consistent one charge was. A velocity flat-spot is about neighbors — how little the average speed changes from one charge to the next. Both only mean something side by side, and both are noisy on three to five shots. (Reading a powder ladder)
4. Bring in the groups. The chronograph can't see paper. Mean radius and vertical come from the target, and at 100 yards they tell you more than velocity does. At long range it swings the other way: velocity SD turns into vertical downrange and earns more of the say.

Can a spreadsheet do it?

Yes, and plenty of good shooters run one. Averages and SDs are easy formulas, and ShotView will share any session out as a CSV. What takes the work is everything around the formulas: lining sessions up with charges, dropping the fouler, typing in group measurements from a separate tool, and deciding how much each number should count at your distance. That last part is where most spreadsheets stop, and the call goes back to eyeballing a chart. (Spreadsheet vs. software, the honest comparison)

What Loadscope does with a Xero ladder

Plug the Xero into your computer and Loadscope lists every session on it, grouped by range day, with the block that looks like your ladder already ticked. You confirm. It pairs each session to its charge by firing order, sets short foulers aside, pairs each group from your target the same way, and scores every charge on velocity flat-spot, velocity SD, mean radius and vertical, weighted for the distance you shot. Then it names your best load and tells you whether your velocity data is strong enough to back that call up.

Nothing is written to the Xero, and nothing leaves your computer.