The serpentine lock – the earliest known form of trigger – is depicted in Johannes Hartlieb’s Kriegsbuch from 1411. This guy has reproduced a handgonne with this kind of lock.
Here, the same guy is readying and shooting his handgonne:
The distance to the target is not far, and his shooting conditions are perfect, but it is still a reminder of that the handgonnes of the age had at least decent accuracy, which made them usable in combat.