My old KWA G18C was doing fine till about a half dozen parts failed simaltaneously. I got a new one and will be more careful with this one. The only problem is the damn thing seems to want to fall apart. The gas chamber block screw (part 18) keeps unscrewing after firing off maybe one or two standard mag's worth of shots. If I don't remove the slide and screw it back in, the slide locks up and I can't take it off, unless I use brute force and some tools to jimmy it open. The other problem I'm having is that the lever alignment pin (part 258) keeps popping out, sometimes during firing, and sometimes it just does it when I'm not shooting it. Just today I was firing the gun and I lost the lever alignment pin, luckily the broken G18C still had its lever alignment pin, so I took it out and stuck into my new one. This time I stuck a little bit of tape on it so that it won't fall out when I'm not looking.
I just got this new one a week ago, I haven't been firing it non-stop everyday or anything, just intermittently every two days or so.