The Satterlee 10-Round Load Development Method

The Satterlee method is a fast load-development test: fire 10 rounds, one each at 10 charge weights stepped up across the safe range, over a chronograph, and look for a run of consecutive charges where velocity barely changes — a flat spot that suggests a stable charge window. It’s quick and genuinely useful for scouting, but with a single shot per charge it’s a starting point, not a verdict.

Named for Scott Satterlee, the appeal is obvious: ten rounds and one range trip to point you at a promising charge, instead of shooting groups at a dozen charges. Used the right way it saves barrel and time. Used the wrong way — treating that flat spot as a finished load — it burns both. Here’s how it works and how to read it honestly.

How to run it

Work up your charges in even steps across the safe range for your cartridge and bullet — always start low and work up, watching for pressure the whole way. Load one round at each step. At the range, chronograph each shot in order, from the lightest charge to the heaviest, and write down the velocity for every one. That’s the whole test: ten shots, ten velocities.

What you’re looking for

Plot velocity against charge weight and you’re hunting for a flat spot — three or so charges in a row where velocity climbs only a little between steps, forming a plateau before it takes off again. The idea is that a charge sitting in that plateau is a little forgiving: a small metering error or a temperature swing nudges velocity less than it would on a steep part of the curve. That’s the charge window the test points you toward.

The honest catch: one shot per charge

Here’s where people get burned. Every velocity in a Satterlee ladder is a single shot, and a single shot carries all the normal round-to-round scatter. That means a “flat spot” can appear purely by luck — two neighboring charges happening to land close — and vanish if you shot the same ladder again. It doesn’t make the method useless; it makes it a scouting tool. It’s good at saying “look around here,” and bad at saying “this exact charge is the one.”

How to use it well

Treat the flat spot as a lead, not a conclusion. Once the ten-round ladder points you at a charge window, go confirm it with a real string — several shots at your one or two favorite charges — so the velocity consistency and the group have enough rounds behind them to be believed. Scout wide and cheap, then spend your rounds proving the finalist. That’s the difference between a method that saves barrel and one that sends you chasing noise.

Where Loadscope fits

Loadscope reads the chronograph data from a ladder like this, finds the velocity flat-spot for you, and — once you add a confirming string and your target groups — scores every charge on velocity flat-spot, SD, mean radius and vertical to name your best load. Because it’s doing the math, it also makes it obvious when a flat spot is thin on shots and worth confirming before you trust it. See how the scoring works →