I did the same thing recently. Bought an inexpensive light/laser combo for my 24/7 home defense gun. I took the setup out to the range after zeroing in the laser at 21 feet. After 1 mag, 15 shots the light lens was covered with powder residue. I was shooting outside in daylight so I don't know how the light was truly affected but it was severely darkened. The second mag saw the laser go out on the 4th shot. It seems the entire insides blew out forward from the pressure of a battery spring. The wires all disconnected, rendering the light useless as well. The unit was a cheapy in the $50 range. Glad it happened during a range session and not in an HD situation. If I do it again, I'll only buy a reputable unit with a warranty at a gun shop.