How is a group properly measured?

[gamestalker]

Even though I've been hand loading for nearly 30 yrs., and punching paper and hunting for much longer than that, I don't know how to measure my groups. I regularly shoot my high powered rifles at 200 - 300 yds. and though I think my groups look impressive, I'm unable to determine how impressive. Yesterday I was putting some groups on paper at 200 yds. with two different 7 mags.. I shot three 5 shot groups from each rifle, with each group being a single hole. I tried to measure the groups and came up with the largest .610" and the smallest it is .435". If I knew anything about how to post pictures, I would have someone take a look and then demonstrate how it's done. I took the largest point to point, other wise the group would measure considerably less, and I didn't think that to be an honest evaluation.
Thanks for the anticipated help.

 

[Canuck-IL]

http://www.thehighroad.org/showthread.php?t=521577&highlight=measure+a+group

http://www.thehighroad.org/showthread.php?t=194398&highlight=measure+a+group

Doesn't anyone use the Search...?
/B

 

[rcmodel]

Measuring to the outside edges of the two widest shots in the group, then subtracting one bullet diameter is the group size (center to center of the bullet holes).

Myself, I don't get that precise and mathematic, and just measure to the left or right side edges of the two widest holes.

rc

 

[dubbleA]

Simplify things.... it's a free download. It's pretty easy to use, just take a pic of your target with some sort of reference ( I use a set of dial calipers set to 1.00").

http://www.ontargetshooting.com/


Here's an example of a 10 shot group

 

[Art Eatman]

First paragraph, Post #3. That method gives the center-to-center distance, and it's the accepted standard for group size since even before I started shooting.