Federal AE .223 accuracy?

[NWPilgrim]

The problem with that page is only is examining extreme spread. Different groups can be in different locations relative to the point of aim. The calculations that estimator page is doing does not include any factor for where the group lies from the point of aim. Also, it is not factoring in how close the shots are to each other. Did you have four shots very close and one outlier? That is statistically very different than four evenly distributed shots within the extreme spread. That is why measuring just extreme spread is almost meaningless and not surprising that you can estimate extreme spread with a few shots.

But as hunters or target shooters when we say "accuracy' it is always in reference to how close to the point of aim. That is why a proper analysis of accuracy ought to measure the distance each shot is from the point of aim and relative to each other. A couple of software programs make this easy using photos of your targets: OnTarget and Shooting Lab. They both capture each shot relative to the point of aim and each other and calculate the average mean radius (distance from POA) and standard deviation. The mean radius is really what we are interested in if we want to know the most likely distance from the POA our bullets will strike. Both SW programs also allow you to overlay multiple targets to create virtual groups with the same POA. The resulting mean average factors in whether you have an excellent group with an outlier, or an overall mediocre group.

So the above estimator only predicts the group size for any one group, but totally is incapable of telling you where any one of those groups will lie relative to the POA.

[Road_Clam]

Originally Posted by NWPilgram

I have see it happen plenty of times. 3 shots that are .5" today can shoot 1" next week, or .3' or 1.25".

A big +1. I've tested over 1000 loads spanning 9 different calibers and I've learned to trust my most repeatable handloads even at the expense of giving up measured MOA accuracy. So I will take a load that will shoot 1.2 moa all season long vs. a load that shot .2 moa in October but then the same exact load shot 2 moa in June. Temps and humidity play a substantial role in maintaining consistency and I have not yet mastered weather variables with my handloads.

[NWPilgrim]

Here is an example of OnTarget analysis graphic. The shot target was uploaded from a phone pic, then the bullet holes placed using OnTarget, a one inch distance was calibrated and the software calculates everything else such as: max distance C-to-C, mean radius, group center, offset from aiming point, maximum horizontal and vertical distance of bullet holes.

[Hopefully I can upload the image correctly]