This is something that is new to me. I have seen it for a while in the Ballistic-X app, but never really paid much attention to it. I have started to hear rumblings from people I respect about how this is the way, so I decided to do some research. This video podcast from Hornady is worth your time if you’re serious about shooting precision and want to truly understand how accurate your rifle and ammunition combination really is.
What’s Wrong With Just Measuring Group Size?
Most shooters are used to measuring group size by the extreme spread, the distance between the two farthest shots in a group. It’s easy, it’s familiar, and it’s what everyone has done for decades. Some with bullshit three shot groups like Mark Laure, and other with five shot groups, all the way up to 20 and 30 shot groups. But it’s also misleading.
Why? Because extreme spread is heavily influenced by just one or two outlier shots. A single flier, whether it’s caused by wind, user error, or an unpredictable round, can wreck your group measurement, even if the rest of your shots were tightly clustered.
Enter the Mean Radius: A Smarter, More Stable Metric
Hornady’s podcast explains how mean radius which the average distance of all shots from the group’s center, gives you a much more consistent and truthful picture of how your rifle and ammo are performing. It’s a statistical approach that reduces the impact of outliers and emphasizes the true average performance of the system.
Video is worth your time if your interested.