Isn't MR fairly linear to dispersion when the groups stabilize?Sort of- what MR won’t do is tell you what size target the system will hit. Or, it won’t do it without charts, and Excel sheets, math, and general time wasters. Using mean radius (as well as large shot group ES) makes sense from a large scale testing and contract process. It does not make sense in the “I need to see if this combo will hit what I need to hit, and zero correctly” process.
Hitting living things isn’t about “average distance from center”, it’s about “worst” shot from center.