Dept. issue weapon is the full size M&P40. Went to qualify this past week. I have always shot high 90% each yearly qual. The shots from this weapon were all very low. Shooting Speer 180 grain Gold Dots. At 25 yards at a Q target my shots were off the paper low. That would be about 12-18 inches low. Is this a know issue with this pistol? Do I need a higher rear sight? I do not have a lot of confidence in this weapon as it is right now and I have to carry it on duty.