The NPatch even allows custom cursors on weapons! These cursors are added using the same process as cursors for superweapons. In essence, these are just custom actions that can be reused on multiple weapons even. However, you should not use any existing actions with this because you will not get the cursor you wanted.

Anyway, in order to even use the new cursor you need to add Cursor=[MouseCursor] to any weapon. However, this logic only works with the Primary weapon. If you set it to the Secondary weapon, it will not work.