Arcane Ammunition

As a bonus action, you touch one piece of ammunition or one throwing weapon. For the duration of the spell, this weapon is wreathed in magical energy, and when it is fired or thrown, it becomes a magical weapon if it isn't already, its damage die becomes a d8, and the item returns to you after it either hits or misses its target, after which the effect ends. 

At higher levels, you can affect additional ammunition or thrown weapons: 2 at 5th level, 3 at 11th level, and 4 at 17th level.