Quote:
Originally Posted by Precisionshooter
If you subtract caliber diameter you will likely get a false measure - one actually smaller then the group really is. To be accurate, you need to measure a single hole on your sheet of paper and deduct this number from the group measure. Be sure to measure the same marks on the single hole as you do on the group hole.
If the group is a little larger so you have distinct holes on the two most extreme holes you can measure on the same side of each hole and not have to do any subtractions with a gage hole diameter (from the paper) or an actual caliber diameter which in most cases (if not all) will give you a false measure.
|
if you want to be very accurate with measuring groups ...
http://ontargetshooting.com/index.html