just a sugestion here but your shooting 'groups', chill out and revert back to single shot one off's.. you'll never group a head shot, unless you like dead targets.(it;s a diferent mind set to 'one shot or its gone')
put up small targets mints or something, forget about them, then just get up for one shot, pick the target and hit whatever the winds playing at, thats the mind set sort of thing, after a while you'll find you can set a ffew pegs in the ground with stuff on top, hit them after replacing several times, but randomly.... after a a while you notise theres a few holes in one place