In the past when people asked about my Glock, I'd just unholster it, unload it, and toss in on the ground. Didn't matter if it was concrete, gravel or whatever.
To make a point once, I let my G27 be used as a hockey puck in a street hockey game.
I should note at this point, my g27 is my daily carry gun, and has quite a bit of "wear". It gets holstered and unholstered 3 or 4 times a day, and has for YEARS. The slide shows the ware. I wear my Glock while bike riding, working out, whatever. Let the sweat soak the darn thing, don't wipe it off, clean it in the dish washer once every two years. Never a problem.
So, my glock isn't the prettiest, but it works fine! (every time, I'd bet my life on it.)
So, getting back to tossing/dropping it. Two things to remember.
The sights aren't polymer, they are plastic. And that sucks. The sights WILL get dinged, and messed up. I keep meaning to replace mine with metal sights, or something else.
Second thing. If it slips from your hand, let it drop to the ground. It will not fire if it hits the ground, but if you try to grab it as its falling and a finger/thumb gets in the tigger guard, the glock will function as designed.
Eric
Owner of a two G19's, G21, G26, G27 and G30.
btw: I'm not a total bigot, I actually perfer the look and feel of my SIG's, but they just aren't as rugged. (They rust, scratch, etc.)