I'm sorry! I got distracted and off course with this. But if you'll stay with me I think I can help you after I quit laughing!
Anyway,,,, back to the five match agg we were shooting. We got through the first three trips to the line in good shape and are now at the top of the leader board with a teen agg! The cases are loaded, we're just waiting for relay three to finish and for the range officer to say, "Relay one, shooters to the line!"
When we started match number one, temp was 60 degrees, tuner was set to 'zero.' After fouling shots and scope adjustment, our first three shot test group was not good, indicating the rifle was out of tune. Maybe not completely out but not what we wanted so the tuner was moved one mark in one direction or the other, I forget which way but that made it worse so we went back to zero and then moved the tuner one mark in the other direction. The next test group was smaller but still had a little vertical. One more mark in same direction and the rifle shot a dot!
So we were in tune with the tuner set to 2 marks 'in' from zero with a temp of 60 degrees. Match one went well.
Things were moving slow with the target crew and by the time the range officer called relay one back to the line for our second match, temp had increased to 70 degrees. My instincts were to bring the tuner 'in' one mark to compensate for the ten degree increase in temp but we decided to leave it where it was and accept maybe a little vertical as the wind had picked up and the group was likely to print more horizontal than vertical anyway. It was a good decision and although the group did indeed measure slightly vertical it was still a good group.
For match number 3, temp was up to 80 degrees so we definitely had to make a tuner adjustment. In match number two, it would have been better if we had turned the tuner 'in' one mark which would have removed the bit of vertical which was reflected on the target. Two marks 'in'' brought the rifle in tune and match 3 moved us into first place.
So here we are awaiting the range officer's call to the line for match number 4. Cases are loaded with exactly the same load used in match number one, tuner is set to four marks 'in' from zero.
Match 4 The range officer calls, "Relay 1 shooters to the line.
Winds have picked up some but temp remains 80 degrees. A two mark 'in' adjustment was made after match 3; one to correct for the ten degree increase from 60 to 70 degrees and another to compensate for the additional increase to 80 degrees. Tuner is now set to 4 marks 'in.' The test group on the sighter verifies that the rifle is in tune so we settle in to watch conditions and decide when to begin shooting. Six minutes remain in which to shoot our five record shots. Winds have been waltzing back and forth from one direction to the other with velocity slowing, becoming all but calm during the switch from one direction to the other. We know this pattern will repeat two or three times during the remaining six minutes so we will be ready when the next lull appears and machine gun our five record shots before wind picks up after the switch.
Sure enough, wind velocity is beginning to let up and comes almost to a standstill as the flag vanes meander about during the switch. This is what we've been waiting for; GO FOR IT! Shoot quickly but carefully, watching the flag tails for the pickup that is surely coming. Shots 1 through 4 go in a dot but as we are loading the fifth round the flag ribbons begin to rise as velocity increases. Do we stop shooting or continue, firing the last round by holding about a bullet hole of correction into the wind? If it was me, I know I would continue rather than stop and have to 'wait and pick' that last round.
And so, that's exactly what we did; fired the last round with a slight hold into the wind as the range officer calls, 'one minute, you have one minute to complete your firing.' And it's a good group! Good enough to hold on to the top of the leader board. One more decent group and we've got it won! 'Cease fire, cease fire, clear the benches, make the line safe.'
), I've fired a BUNCH of groups with my tuners and have established, by a very statistically significant number of rounds fired, groups, barrels, and rifles, that a clear pattern emerges. Enough so, that I'm confident in how far to move my tuner, based on group size and shape. No different than tuning with powder charge and seating depth...you see groups get larger or smaller with changes and even see group shape come into play as well, with either method. While maybe imperfect, tuning a rifle's group size and shape by adjusting powder charge or seating depth, works, and has for as long as we've been shooting. 
