Mean Radius for measuring groups and rifle accuracy

[Hohn]

Except I believe mean radius generally is measured from the center of the group. I’m thinking about score matches, such as Highpower & F-class, and want the radius from the center of the target, regardless of where the group is centered.

I believe you are correct. That’s the difference between precision and accuracy. From the center of the group, it’s a measure of precision. From the point of aim (or target center), it’s a measure of accuracy.

 

[Straightshooter1]

Except I believe mean radius generally is measured from the center of the group. I’m thinking about score matches, such as Highpower & F-class, and want the radius from the center of the target, regardless of where the group is centered.

Mean radius is for evaluating what your gun and cartridges can do. If I know where that mean radius is consistently at, it's easy enough to move it to the center of the target. ES's can't help that way.

 

[CharlieNC]

Except I believe mean radius generally is measured from the center of the group. I’m thinking about score matches, such as Highpower & F-class, and want the radius from the center of the target, regardless of where the group is centered.

I posted a thread a few weeks ago about target statistics which includes an excel program to calculate MR based on the center of the group and the point of aim; it was originally setup for my FClass shooting. You can download it for your use.

 

[wkdickinson]

I posted a thread a few weeks ago about target statistics which includes an excel program to calculate MR based on the center of the group and the point of aim; it was originally setup for my FClass shooting. You can download it for your use.

Would you please provide a link to the specific thread you referenced?

 

[CharlieNC]

Would you please provide a link to the specific thread you referenced?

Target Statistics For Shooters

How many shots are required to statistically show loads are different? It's actually straight forward, and is a bit of a different than you have been led to believe. I discuss this and include an excel program for your use. Caution.... it's nerdy.

forum.accurateshooter.com

 

[Brians356]

If I know where that mean radius is consistently at, it's easy enough to move it to the center of the target.

Mean radius is a length value, a whole number. How do you position a number on the target?
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[Straightshooter1]

Mean radius is a length value, a whole number. How do you position a number on the target?
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Yes, MR has a length. . . and center from which is it measured.

 

[Brians356]

Yes, MR has a length. . . and center from which is it measured.

Mean radius for group size (precision) statistics is not measured from the target POA, it is measured from the center of the group.

From the essay @CharlieNC linked to: "... the radius, each shot’s distance to center (DTC) of the group, and its average (mean radius) ..."
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[Straightshooter1]

Mean radius for group size (precision) statistics is not measured from the target POA, it is measured from the center of the group.

Yes, again.

Apparently, we have a misunderstanding. I'm definitely not talking about the distance from POA to the center of the group. I'm talking about moving the DTC of the group to the POA (the center of the bullseye), which is what we all try to do when zeroing our scopes.

When evaluating the precision of my groups, I want to know that my Mean Radius is as small as possible and be sure that that DTC of that group (from a large number of shots) is at the center of the bullseye where my POA is also. That's all.

 

[Brians356]

Yes, again.

I'm talking about moving the DTC of the group to the POA (the center of the bullseye), which is what we all try to do when zeroing our scopes.

You refer to DTC as if it is the group center itself. It's not. It's a measurement of distance of a shot POI the group center. What you seek to move to the POA (by adjusting the scope) is the group center itself.
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[Straightshooter1]

You refer to DTC as if it is the group center itself. It's not. It's a measurement of distance of a shot POI the group center. What you seek to move to the POA (by adjusting the scope) is the group center itself.
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No. The DTC I'm referring to is the Mean Radius of the group. Mean Radius: the average distance that all of the holes in the group are from the group center. Draw a circle with the Mean Radius distance and place the center of that circle over the POA. I don't think I can make it any clearer than that. ¯\_(ツ)_/¯

 

[Brians356]

Mean radius is the average of all the DTCs measured for each individual shot in the group. It has no role in adjusting your scope to move POI, for that all you need is the location of group center.
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[CharlieNC]

Mean radius is the average of all the DTCs measured for each individual shot in the group. It has no role in adjusting your scope to move POI, for that all you need is the location of group center.
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AND you can calculate the standard deviation of those individual DTC, which gives the ability to perform numerous statistical procedures.