She shot until the gun jammed.

As a fairly serious competitive shooter (my youtube video's) from my experience I can tell you; your average modern handgun works.  Start fiddling with shit, use bad ammunition, cheap magazines (clips go on your belt not in your firearm), or any number of user errors cause guns to jam.  Yes fatigue can cause parts to wear and fail, however in most cases that takes lots and lots of rounds down the pipe.