Performing any sort of statistical analysis on two data points is just a really bad recommendation....in fact it runs contrary to how statistical methods should be employed.

I have come to the conclusion that some people just refuse to try to understand the math behind something. We really shouldn't be measuring group sizes with ES either, it is a bit more difficult but we have apps that should be able to tell you the SD of the distance of each bullet impact from the center of the group.

I think people gravitate to ES over SD as far as muzzle velocity is concerned because they use a small sample size and when compared to a legit sample size, their ES is smaller so it gives them more bragging rights. If you have a legit sample size, you can exclude the upper 2.5% and lower 2.5% and the ES should be 4 times the SD. I don't get why people just dismiss the standard deviation being 68% of the data points falling between +-1 SD and 95% of the data points falling between +-2 SD. When you count all 79 shots from my set you get "SD: 4.12, ES: 19"

My total set is:

2805, 2805, 2805, 2805, 2806, 2806, 2807, 2807, 2807, 2807, 2808, 2808, 2808, 2808, 2809, 2809, 2809, 2809, 2810, 2810, 2810, 2811, 2811, 2811, 2812, 2812, 2812, 2812, 2812, 2812, 2813, 2813, 2813, 2813, 2813, 2813, 2813, 2813, 2813, 2813, 2814, 2814, 2814, 2814, 2814, 2814, 2814, 2814, 2814, 2815, 2815, 2815, 2815, 2815, 2815, 2815, 2815, 2815, 2815, 2815, 2816, 2816, 2816, 2816, 2816, 2816, 2816, 2816, 2817, 2817, 2818, 2818, 2818, 2819, 2819, 2819, 2822, 2822, 2824

If we remove the top and bottom 2 data points (1.975 but I am rounding to 2, although in this case the value doesn't change since we are only excluding 2824 {removed two 2805's still leaves us with a min of 2805 and removing 2824 and one of the 2822, we still have a max of 2822} ), we get an ES of 17 (Expected being 4.12 * 4 = 16.48). Now compare that to an example from this thread: "SD 4.3, ES 12". If your ES is less then 3 times your SD, you don't have enough data points AKA you have low as fuck confidence level.

People say shit like "I use ES because that one high or low velocity will cause me to drop a point." Like OK bro, you keep on spitting in the face of mathematics and trick yourself into believing that powder charge A with SD of 4 and ES of 12 is better then powder charge B with SD of 4 and ES of 20.