First of all, this topic is totally irrelevant if you are shooting inside 400-500 yards. This topic was meant for those shooting at ranges where the bullet time of flight is over 1 second (around 1000 yards). The difference on between .5 MOA and 1 MOA accuracy matters not on an eight inch vital zone at 500 yards. At that range, establishing consistency of your load with 3-5 shots is plenty.

But consistency and statistical significant are not the same, and at 1000 yards the difference between .5 MOA (5.3 inch group) and 1 MOA (10.5 inch group) accuracy matters on an eight inch vital zone. At this range I want to know if the statistical probability of a shot landing within the 8 inch vital zone is 50% or 95%. You can absolutely establish consistency of a load with much less than 30 data points, but most statisticians agree that 30 data point is a minimum for establishing statistical significance, which is needed to produce valid probability percentages. Understanding math, science and statistics is not necessary to shoot inside 500 yards and many on this forum have no interest in, or even detest, them; I get that. But they become extremely important outside 1000 yards.

Second, the engineers/ballisticians at Hornady never advocated just shooting 30 shot groups. A three shot group can absolutely tell, with confidence, if a load is not accurate, adding shots to it won't shrink it. But a three shot group is never going to establish the true capabilities of a load, never! They recommended an initial 3-5 shot group using a reasonable powder charge and seating depth. If it doesn't meet your group size goals, then dump it and swap powder or bullet and repeat until arriving at a group size that meets your goal. Then shoot 20-30 in string sizes appropriate for your particular rifle/application (ie. 1-3 for hunting rifle, 10 for PRS or F-class). Plot the x and y coordinates (measured from point of aim) of each shot on a single graph and crunch the numbers to get a mean radius and standard deviation.

The engineers/ballisticians at Hornady postulated the following hypothesis:

Small changes in power charge and seating depth have inconsequential effects on accuracy over a large (statistically meaningful) sample size.

A writer at OutdoorLife, unaffiliated with Hornady, independently verified the hypothesis with regards to powder charge weight.

https://www.outdoorlife.com/guns/rifle-nodes/
Arguments against the hypothesis based on your deeply held religious beliefs about velocity or seating depth nodes, personal experiences with 3 shot groups, or because it contradicts or is different from "how you do it" are no more valid than the "because I said so" argument and make you look arrogant and unintelligent. If you want to disprove the hypothesis, the only valid way is to repeat the test yourself and present the data.

I would challenge the naysayers to shot a composite 30 round group (string sizes appropriate for your particular rifle/application) at your optimal seating depth and at the worst seating depth (within reason) from your ladder. I predict two things:

- Your 7 pound, pencil barrel hunting rifle is not a 1/4 MOA shooter
- The two groups will not be statistically different, that except in very rare cases (pun intended), small changes in seating depth make no difference.

It is a win/win for everyone . You get some extra time at the range doing what we all love, you might learn something new and you can participate in the scientific method and help advance our shooting community. For those that are not comfortable crunching the numbers, I am happy to help with that at no cost.