If I take a bullet with a G1 BC of 1.5 and shoot it at 750 fps and 850 fps at 25 yards, the difference in drop is about half an inch. If your groups are not that small, you probably can't see that 100 fps spread at that range. At 50 yards it grows to 1.7" and some of the very best shots might notice. At 100 yards it is about 7 inches, and that would be noticed.
What determines your best accuracy is likely to be something else.
Because of chamber variation, revolver accuracy smiths typically ream the chamber throats to the maximum SAAMI diameter as the first step toward accuracy. They will tune the alignment of the chambers with the barrel by shimming or replacing the cylinder bolt. They make sure the cylinder latching mechanism is tight. Indeed, some custom gun makers have gone so far as to under-bore the chambers, then use a special boring tool that centers in the barrel to take the pilot cuts for the chamber reamer, ensuring alignment at each position. All this is considered important to get the most out of your ammunition.
Regarding ES and SD, as FlyFish mentioned, SD can get smaller or larger with sample size. It is an estimate of population standard deviation (sigma, σ), so whether it grows or shrinks with additional events increasing the size of the sample just depends on whether the initial sample has over or underestimated σ. Board member Statshooter teaches statistics for a living, and he doesn't trust a sample smaller than 30 for getting a good estimate of population SD.
ES grows with sample size. This is because a larger sample includes more opportunities for less likely wider-spread data to be included. On average, over many samples, you will find ES is a multiple of the SD. And, indeed, for a sample size of 2-7 or smaller, dividing the ES by the expected ratio of ES to σ, ξ
, results in a more accurate estimate of σ than the sample standard deviation computation by your chronograph does. This is due to bias that exists in the standard sample SD calculation. You can look at
unbiased estimation of standard deviation in Wikipedia as a starting point if you are interested in the subject. But in the meanwhile, the expected ratio of ES to σ has these values:
Code:
Sample Size ξ(n) (ES to SD ratio, on average)
2 1.128
3 1.693
4 2.059
5 2.326
6 2.534
7 2.704
8 2.847
9 2.970
10 3.078
15 3.472
20 3.735
30 4.086