I just bought an x300 for my gen 4 glock 17. I installed it as per the directions and everything went fine. But if i push and pull on the bezel to test the mount there is a very slight amout of play back and forth. I tried both mounting methods and both are the same way.
I took it to the range and shot my local action pistol match and had 4 double feeds and 2 stove pipes in approx. 150 rounds. I have about 3000 rounds down the pipe total. 1000 of those had a TLR-1s attached with no problems.
The question is: Is the play between the light and the gun normal? And: could this be causing my malfunctions?
I suppose if the light is bouncing fore/aft during shooting it could be… Try loosening all the allen screws holding the rails on, and then tightening them while pinching the rails together. This will make for a much tighter fit. A bit of blue loctite on each screw couldn’t hurt either. Also, make sure you are using the correct “U” plate for Glocks.
Good luck!
Dennis.