Fusil of Conflagration

In your shooting phase, you can pick 1
enemy unit within 12" of the bearer and
visible to them and roll a dice. On a 1, this
artefact cannot be used again for the rest of
the battle. On a 2-3, nothing happens. On a
4-5 that enemy unit suffers D3 mortal
wounds. On a 6, that enemy unit suffers
D6 mortal wounds.