The fiery touch of Pheonix

When you touche a melee weapon, a quiver with arrow or bolt, a firearm. When a target is hit by the weapon, it suffers fire damage instead of normal damage. The magic of the spell ends on the ammunition when it hits or misses, the spell ends when twelve rounds of ammunition have been drawn from the quiver, and the spell ends if the firearms misfire. The magic of the spell ends on the melee weapon, if  you lose concentration or if you lose your weapon.