I just got my sigma 40 and went to the range and was shooting really low. I have read that sigmas need to cover the Target instead of just below the Target. But even with that would not make a difference because I was aiming for the head and the shots where hitting the center of the Target like 7" low. This at 7" yards. I put 100+ rds. And all seem to be low. Also it seem the higher I would go on the Target the worst it got. Is it me new with a sigma or is the front sight to tall or something else? What step should I take.