IT mistakes are frequently glaring plot-holes that render entire sections of the story impossible. Gun mistakes are generally a choreography problem, a weapon that's possible but just hasn't been manufactured, or someone learning information about the gun's state via the wrong channel (where such an information channel does exist).

Sure, sometimes a bullet impact throwing someone off a cliff is plot-relevant, but I couldn't name a single example. On the other hand, I can think of several examples where (supposedly) state-of-the-art encryption is cracked digit by digit, or where a radio receiver is tracked from a distance where the receiving pattern would be orders of magnitude below the noise floor (most often from orbital satellites), or where a device is remotely "hacked" that is not even plausibly connected to a network (less common, now that everything is IoT, although it's really prevalent in works set in the late 90s / early 00s).