Repeating Shot

Source: Tasha’s Cauldron of Everything p. 22
This magic weapon grants a +1 bonus to attack and damage rolls made with it when it’s used to make a ranged attack, and it ignores the loading property if it has it.

If the weapon lacks ammunition, it produces its own, automatically creating one piece of magic ammunition when the wielder makes a ranged attack with it. The ammunition created by the weapon vanishes the instant after it hits or misses a target.