Satterlee 10 Round Load Development

[Harpoon1]

It appears to be Satterlee. You fire single rounds over the chronograph in a ladder and look for velocity nodes. Then fire groups at the node.

How do you know all the other increments wouldn't be better groups?

I have done a few thing over the years but am starting to settle on this.
Work out a max from QL manufacturer tables and shooting forums.

From the max go back ten 1% increments. So if the max is 28.5gns these are the increments;
28.5
28.2
27.9
27.6
27.4
27.1
26.8
26.5
26.2
25.9

The lightest load comes out at about 10% below max which is a good start.

Then load 3rd for each step and shoot these on targets while recording the velocity. Look for the tightest group closest to the max while noting the velocity curve.

It's 30rds or if you want to shoot two groups per increment then it's 60rds, a decent shooting session.

Define “better groups”?

Just my opinion but, I get the sense Satterlee in not looking for the most “accurate” load, i.e. tightest groups per se. He’s looking for the most “durable” load, most “forgiving” load with acceptable accuracy, for PRS style competition. It’s just his shortcut to Newberry’s OCW method. Searching for the largest node, closest to the maximum safe charge. Once he’s found the node, then he fine tunes accuracy with seating depth. The goal is to be able to load in volume on a progressive press and know a tenth or two on either side of the target charge weight would have little to no affect on POI.

Whereas someone shooting in another discipline might have a different definition of what is “better”.