Load'EmGuide
OCW load development, step by step
The goal is not the smallest group you ever shot. It is the charge weight where small changes stop mattering.
The idea
Optimal Charge Weight, developed by Dan Newberry, looks for a window rather than a point. Somewhere in a powder range there is a band where the barrel's harmonics put the bullet out at a consistent point of impact, and where a few tenths either way barely moves it. That window is what you want, because temperature swings, lot changes and small metering errors will move your charge around whether you like it or not.
A load that shoots one brilliant group and then falls apart when the weather changes was never a good load. It was a lucky one.
Running the test
1. Set your range
Start from published starting data and work up toward, but not beyond, published maximum. Choose an increment that gives you 7–10 steps across the range, typically 0.3 to 0.5 grains for a mid-size cartridge, less for small ones.
2. Load three rounds per step
Three is enough for the point of impact to show. Keep everything else identical: same brass lot, same primer, same seating depth, same neck tension.
3. Shoot round-robin
This is the part people skip and it matters most. Shoot one round of each charge in order, then repeat, rather than firing all three of one charge together. That spreads the effect of a warming barrel and changing conditions across every charge instead of loading it onto the last one.
4. Watch point of impact, not group size
Plot where each charge's group centre lands. You are looking for two or three consecutive charges that print in the same place. That flat spot, the scatter node, is your window. A single tiny group between two charges that print somewhere else is noise.
5. Take the middle
Load the centre of that window, not the edge. The whole point is having room either side.
Safety, every time. Work up from published starting loads using current manufacturer data for your exact components. Watch for pressure signs at every step and stop when you see them. Never start from someone else's "pet load" off a forum, including anything you read here.
What to record
A test you cannot reconstruct later was a waste of components. At minimum: charge weight, the point of impact, group size, muzzle velocity if you have a chronograph, temperature, and which brass and primer lot you used. Lot numbers matter more than people expect: a new lot of the same powder can shift the whole window.
OCW versus the Satterlee ladder
The Satterlee 10-shot method looks for a velocity flat spot instead: one round at each of ten charges, watching for consecutive charges where velocity barely climbs. It burns fewer components and takes one range trip, but it leans entirely on chronograph precision, and with a single shot per charge it is more vulnerable to a single odd reading.
In practice many people run a ladder first to narrow the range, then confirm with OCW groups. Load'Em supports both, and keeps the results attached to the rifle and load they came from.