There seems to be something odd going on with the shortbows low damage rating. I wasn’t able to get arrows to get more than a few tiles, despite having a listed max range of 12. If you repair your bow it might fix itself, since damaged ranged weapons lose damage value and that seems to be the cause of whatever is going on.
EDIT: When I play, the shortbow has a listed range of 12 tiles. Yet the game has it listed as a range of 4 in the code. What does the game list for your range when you go to fire the shortbow?