for a moment i thought you were asking for help with my musket weapon lol
do you have two versions of this mod? right now it seems to be using the "musketBasicProjectile" projectile datablock, but that datablock is not created in any of the code inside the zip you posted. if shooting is working ingame, some other mod you have enabled must be creating these datablocks, the most likely candidate being the older version of this mod. or the pirate pack by gcat, but i dont think that's where the projectile comes from.