measuring groups- which way?

[captwoody]

I dont think i am measuring my groups correctly is it outer edge to outer edge or furthest center to center.I have been measuring outer edges so my groups may be better than posted

[RatRacer]

I've always thought it to be C to C, edges are collateral damage.

[MustangMike]

Center to center of 2 farthest away holes.. or use change put a dime on the group. Or a nickel, quarter, silver dollar etc...

[Motorhead]

Or measure OUTSIDE edges of spread and deduct diameter of one hole. This will give you an ACCURATE center to center ... CTC of your group

[Ribbonstone]

A word about anal retentive group measure. When you test close, have to measure close to get any good from shooting. Cheap printer paper tends to not show clean cuts from pellets, especially when the pellets strike the edge of an already formed group.

Lay the Target on a contrasting sheet of paper.

Flatten out the cheap printer paper.

Locate the centers of the farthest pellet hits.  Often those will be kind of pressed in, not making a full sized hole.  But by looking at the lead smear, can figure it out if you are honest with yourself.


Mark centers.

Draw a line between the two centers.




Draw a right angle line through each of the outer pellet holes.


End up with something like this.  Measure between the lines.

[Shoot Straight]

You measure them from center to center from the farthest two pellets.

[captwoody]

THANKS FOLKS  as usual i got all the information i needed plus some pointers, plus now i know my groups posted are actually.22 of an inch smaller

[rsterne]

Groups are technically measured C-T-C.... However, if you can cover the group with a dime, it measures 1/2" C-T-C or less, depending on the caliber (exactly 1/2" for .177 if you can "just" cover it)....

Bob