has anyone done any testing of striking surfaces with these types of heavy flashlights to see if they actually hold up?
I have, with a Streamlight SL20. My striking surface has been between the belt line and the bottom of the rib cage, usually with a wrist pop just prior to impact. I hold the bulb end, and strike with the other end. I find it easier to keep control of the flashlight this way. Every time, it had the desired effect...to back the person up and out of my personal space. (A good rule to remember: Don't try to intimidate the nice officer, especially us older ones.) I have also shined the light in people's eyes at night while they were advancing towards me. It stuns them for about five seconds, enough time for me to side step their advance and determine what, if anything, I want to do with them. Most were simply drunk (and therefore being stupid).
I only had one flashlight ever damaged. Not by dropping it down a flight of concrete stairs or putting it through a side window of a car, but when it was ripped from my hand by a German Shepard named "Misha". (I learned the name later.) I was walking onto his property to interview a witness, and the dog appeared out of nowhere and lunged at me. I had my flashlight in my hand and brought it up in front of me, and the dog took it and tore it into several chunks. By then, the owner appeared and took control of the dog. He was quite nice once we were "introduced".