3.9 of SP
Average- 1002.8 FPS
Power Factor- 124.347
4.0 of SP
Average- 1017.6
Power Factor- 126.182
4.1 of SP
Average- 1022
Power Factor- 126.765
4.2 of SP
Average- 1056.66
Power Factor- 131.026
Regarding your data:
First, you will do yourself a favor to round the decimals off the velocity and PF numbers. It doesn?t help for you to consider those decimal spots, so probably best of you just ditch them. And since power factor is about reaching a minimum, probably best to round down. A PF of 24.9999 still fails to meet power factor.
Okay, so your 3 incremental velocity gains for increases in charge weight are 15, 5, 34. There are a few ways to account for that.
One is simply that the shinier the projectile, the less precisely the chrono will read them, and XTreme makes shiny shiny bullets.
Two is how you are setting up your drop. You should measure your charge weight with 10 drops and divide by ten for your average drop weight. And whereas it?s pretty useless to calculate decimals for velocity and PF, it can be helpful with charge weights. I?m never going to report load data in this forum with 4.13gr, but I do keep those notes, and I can often see those decimals reflected in the velocities. For example, your 4.0 could be 4.03, your 4.1 could be 4.07, and your 4.2 could be 4.23, so instead of your final to increases in charge weight being +0.1, +0.1, it?s really +0.04, +0.16, and that would account for not all but a lot of the odd numbers you see.
Three ? you haven?t figured out how to set up your chrono well enough.
Four ? your powder drop throws the occasional wonky charge.