Worked once - AimShot Universal Laser Boresight Pistol Kit

Bought for 9mm Taurus PT111G2 pistol. Installed light and gently closed slide, but would not close all the way - which is required for tilt barrel pistol. Gave slide a tap and it closed completely. Light was bright enough in dark basement and adjusted iron and laser sight. Removed from bore and removed back cap to preserve batteries. Reinstalled, tapped slide, and ... no light. Best I could get after that was a very dim light, which would flash bright momentarily about 1 revolution from bottoming when screwing on cap. FAQ on AimSHOT site suggested removing extractor spring. Would have been nice to know up front in directions. Looks like I now have a nice, small, zippered pouch for tools for my range bag.