Went to the range yesterday to sight in the Insight X2L Laser/Light. I know the pistol is dead on and very accurate. I then sighted in the Laser manually and witness it to the iron sights. The first shot with the laser was dead on then after a few shots the laser was off. I played this scenario for a half hour when I realized that after a few shots the light shifted on the frame very slightly. I then took my Glock out and put the X2L on that and it's rock solid with zero movement. The laser held a zero while on the Glock. I then put the X2L back on the HKP2000SK and confirmed a slight movement which through the laser off a few inches on the target. I found yet another reason to go back to my Glock. I am becoming very disappointed in the P2000SK the more I shoot it and carry it.