my what a strange and confusing answer from meddler!
Lets get back to the original query and although it pains me the best answer has come from Tom but a little blunt as is his way

If you struggle on 3 spot indoor face look towards your posuture which must be very bad to cause what you are talking about. It must be very bad when you consider the difference in angle between the 3 targets and shooting on a field course which has some serious changes in angle from the average shooting hall

shoulders, over hips over heels should cure the problem
And as to unit aiming lets not even go there!!!!