[Ripper]

Initially, I thought you measure groups by the size if the diameter that circled ALL your shots, even the strays.
Then I learned that it was the diameter of the majority of shots that were closest together, not including strays.(This is the one I always went by)
Then again, I was shown that you only measure the tightest shots.
Then someone said, you measure groups by the distance from one shot to the other.

 

[Las Vegan Cajun]

This quote came directly from my Lyman 47th reloading handbook.

Reloading is what makes the sport of benchrest shooting possible, wherein a group measuring 1/4 inch from the centers of the two most widely separated shots won't be good enough to get the shooter an honorable mention at a serious match.

Looks like the accepted method is from center to center of the two most widely separated shots, I take this to mean all of the shots in the group.

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[BB]

I measure a group of shots. If I'm grouping 5, I count all five regardless of flyers. I measure between the shot centers of the two farthest apart.

 

[Mark IV Series 80]

I measure to the far edges of the holes that are furthest apart, and then subtract the bullet diameter from that measurement.

I believe that this method is more accurate than measuring to a spot on the target, (the center of the hole) that is no longer there.

-Mk.IV

 

[KLN]

The accepted standard is center to center of the farthest shots. It is sometimes easier to measure the center of the hole than the edge, since edges are often indistinct, particularly with rifle bullets, while the center of the hole is visually easy to discern. The difficulty is when there is more than one bullet in the hole, in which case the edge to edge minus a caliber may be easier.

 

[jrchilds]

Yardstick

 

[Mark IV Series 80]

Originally posted by KLN:
The accepted standard is center to center of the farthest shots. It is sometimes easier to measure the center of the hole than the edge, since edges are often indistinct, particularly with rifle bullets, while the center of the hole is visually easy to discern. The difficulty is when there is more than one bullet in the hole, in which case the edge to edge minus a caliber may be easier.

Hello KLN,

That is true, when using bullets other than wadcutter or SWC.
Sometimes it's hard to tell if the bullet broke the next higher scoring ring.
In this case, we push an unloaded bullet of the correct caliber through the hole to it's full diameter. This makes it easier to score the target.
With FMJ rifle bullets, you could push unfired bullets through the holes, on a flat surface, and then measure bullet tip to bullet tip.

[This message has been edited by Mark IV Series 80 (edited 10-13-2001).]