Thunder Bullets

You touch a quiver, cartridge case, ammunition pouch, or firearm-loading kit containing bullets, shot, or cartridges. Until the spell ends, each piece of ammunition drawn from the container deals an extra 2d6 thunder damage when it hits. The spell ends after twelve pieces of ammunition have been used.

At Higher Levels. When you cast this spell using a spell slot of 6th level or higher, the number of pieces of ammunition you can affect with this spell increases by two for each slot level above 5th.