I always have some doubts regarding the dating inscription on the barrel. So far, I know almost no weapons from the 14th or early 15th century, carrying a makers year. Also on other objects, such as tools, paintings, sculptures, furniture, from the same period dating inscriptions are rather unusual. My doubt is based on statistical facts, but from my experiences with objects from that period so far. If it is indeed a contemporary inscription, this would be an exceptionally rare piece of paramount importance.
My fears about such pieces are always that they may be manipulations from the 19th or early 20th century for the art trade market.
But I hope that I am wrong