I don't understand why this empty moves

So I’ve been making an FPS game like pretty much everyone who uses BGE, lol
but I’m having a problem with the empty that adds in the bullet, I have no idea why and I don’t remember creating any logic that could mean that it moves… I think it’s best explained in the file:
fpsgame-client.zip (1.83 MB)
fpsgame-client.zip (1.83 MB)

The empty is called “barrel” by the way.

The empty is parented to the camera which moves around. Child objects will copy their parent’s translation and rotation in game.