You guys spying on us playing Settlers in the office?
There were certainly gun powder type weapons in the late 13th century in Europe, and by the 14th they were a common sight (albeit expensive and cumbersome). For us at this point though, it's a thematic choice to exclude gun powder and such, not a historical one.
"If they add ninjas". That is a pretty huge if 
Ah so great to hear,you just need to find a good balance for the gun,I already pointed out how it should work. It should have a big reload yet enough to be able to fire 4 rounds per minute,some heavier handgonnes need to be rested in a wall or you get a penalty , etc.