Was your group fired all 10 at once, or in groups of three like you indicated either?
Re: group size. Even if you did eliminate the last 2 shots (not saying you should, just hypothetically) its really easy to see that if you took a random 3 of the other holes it would indicate a different “zero”, as well as could shrink the group extreme spread (talking dispersion here) significantly, with the next three printing elsewhere. On an extremely accurate rifle it might not change the zero more than a scope click, but on most rifles it does change the zero more than a scope click. Thats really the only point, that until you can see that entire bell curve of dispersal, you cant really say whether your zero is accurate to the nearest click, and not knowing the true extreme spread of dispersal you cant say that one group “moved” relative to the other. If you have a crazy accurate rifle setup and your group goes from .2-.4 moa 3-round groups, up to .6-1.2moa 10-round groups, thats still the exact same rifle with exactly the same precision. The only difference is that a larger shot-count group tells you something about the entire bell curve, while a 3 or 5 round group simply gives you few-enough data points that it doesnt tell you much until you overlay it with more data points.
Re: the chucks. Just b/c the extreme spread of the big group is 1.2 or 1.5 moa, doesnt mean that MOST shots dont still land near the center of that group. So you’d expect a first round hit on a smaller target to still happen MOST of the time.
67% of the time within 1sd, 95% within 2 sd, and some very small part farther out. It just means that if you get a few shots once in a while that land 2+ standard deviations from the center of the group, that you know what that represents. Not necessarily a “flier” or “heat stringing”, but a statistically predictable result some small % of the time.
