Group size

Today I went to the range and shot a 10 shot group at 100 yards to see if I screwed up the crown of my AR by polishing out a nick using a hemispherical machine screw chucked into a hand drill.

I don't normally shoot from the bench, but this was confirming the accuracy of the weapon system as opposed to testing the accuracy of the weapon operator.  My group gave me an interesting result.

Extreme spread for the 10 shot group was 2.375 inches, subtract the furthest flyer and the ES dropped to 1.5 inches, and if you drop the furthest out then the 8 shot group went to 1.25 inches.  These are edge to edge minus a caliber using a ruler that is only calibrated to the 1/16 of an inch, so excess digits are me converting fractions to decimals and not actual precision measurements.

What is even more interesting is that the 10 shot string was a 98-1X using a 20 yard rapid fire pistol target at 100 yards.  Not going to win any benchrest competitions any time soon, but more than adequate for High Power shooting.  The 20 yard rapid fire pistol has a smaller dimensions than the High Power SR-1 target, so I'm pretty sure that the score would be higher on the actual target.

Something that screwed me up at my last match was that my thin sight post got lost in the black of the target, using the smaller pistol target meant my front sight post could cut across the black of the target and let me know when it was cut in half for vertical elevation control.  This might mean I need a fatter front sight post to help keep my shot placement steady.