Here’s the velocity plot which goes with my orange dot target above. The groups in the target above are all good, but don’t tell the entire story.

So how do we analyze the groups?

Option A) smallest group. The smallest group on that page is 42.0grn (bottom left target).

Option B) 100yrd OCW flat spot. The centers of groups for 41.0-41.6 are very flat (too left 4 groups) with a bit of wiggle above from 41.6-42.4 (top right 2 plus bottom 3).

Option 3) Satterlee method. The flat spot between 41.6-41.8grn is compelling - especially considering there’s only 7fps ES between all 6 shots at 41.6 and 41.8.

So which option?

Option A might win a 100yrd benchrest Match, but there’s about 30fps spread among a +/-0.1grn powder charge error around that group, which could mean 4” or so in vertical at 1,000yrds. We shoot big targets in precision rifle matches, but 4” extra just isn’t productive.

Option B: same deal - there’s more velocity variation in the lower node than the high node, and that target flat spot covers outside of the node. If I had shot this at 300-600yrds, that vertical spread would have shown itself, but since it was just at 100, it didn’t. I’d likely be ok loading 41.0-41.4, pick 41.2 in the middle there, but given the Satterlee velocity info, that span does have more velocity variability than my middle node at 41.6-41.8.

Option C: if I’m shooting matches at 300-1400yrds, vertical dispersion due to velocity variability matters a lot. So I personally picked 41.7grn, splitting the middle of that flat spot in the velocity curve. It’s made impacts on 1moa targets out to 1200, and half MOA targets to 900, even on the clock.