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Sorry if this has been resolved before but after searching high and low I could not find a specific answer to the following question:
May an Ogre Hunter fire into an enemy unit that is in combat with -only- his Sabretusks?
For example: An Ogre hunter's Sabretusks are in range of a unit of 10 Chaos Warriors and he sics them on the enemy unit. Assuming that they make the charge and the targetted unit does not flee, may he (in the subsequent shooting phase and any thereafter) fire into this unit using his Harpoon Launcher as long as they are only engaged by his Sabres and not any other Ogre unit
The reason I was unsure about this is because the Ogre Kingdoms army does know a "Life is Cheap" rule a la Skaven in the form of them being able to freely draw LoS through Gnoblars with ranged weapons as described in the Bangstick entry
The Bangstick is a magic item with a specific ability. That's why it's allowed to go through the gnoblars. The hunter's harpoon can't shoot into combat because it's a standard shooting attack.