(This farging software won't print a table right-see the attachment.)
MATCH GROUP RATIOS
The CBA data is for CBA NM 2000-2013, PRO, PBB, HVY and UNR, group averages.
The 5 shot issue 100 yd data is from Ric Bowman, Military matches from 1006-2015 =10 years.
The numbers are ratios of group size averages, 2ND/1ST = second place average group size/first place average group size.
Something is going on here, these ratios are remarkably constant, and suggest to me that there's something here that explains at least part of group size.
The second place shooter shoots groups averaging ~20% bigger than the first place shooter.
The second place golfer doesn't average ~20% more strokes than the first place golfer, does he?
The second place baseball team doesn't average ~20% less runs than the first place, does it?
Football?