Ewwww
Guns..?
As in matchlocks and firelocks, not modern weaponry. Certain rolls would lead to misfires, explosions etc - I made up an entire table just for firearms. The PC's absolutely loved them and I loved having them too (not much you can do but surrender in the face of a well drilled group of NPC's formed up with arquebuses facing you). Don't knock them if you haven't tried them!