Hornady have produced a series of podcasts about various aspects of shooting & reloading. I linked one on Barrel Tuners which has prompted some interesting comments.
Delving further, I've come across a series looking at the impact of sample size on load development, which pretty much rubbishes the normal ways I've used (eg Ladder / OCW). The podcasts are long and detailed, but my takeaways from it are:
1. To get a representative idea of group size, you need to fire about 30 shots.
2. Conclusions based on smaller number of shots (eg 3 and 5 shot groups/velocities) are invalid. Using exactly the same load, you are likely to shoot very different 3 and 5 shot group size, velocities and/or zero position.
3. You can use small samples to identify 'bad' loads, but not 'good' ones; if a three shot group measures 3MoA, it cannot get any smaller. But a group measuring 0.5MOA can only stay the same or get bigger.
4. Their load development process consists of throwing different combinations of components at the rifle to see which ones work. No powder charge work-up or seating depth changes; with large sample numbers they find that there are no 'nodes'.
I'm going to try shooting ten five-round groups of my favourite load . . .
Triffid