You’re not supposed to shoot fireworks in city limits. That’s probably one of the most abused parts of the city code, but it’s in there.
The code says: "No person shall … use or explode any fireworks within the city limits." Toy paper caps containing not more than 0.25 of a grain of explosive composition per cap are exempted. Also, public displays are legal provided that a written permit is granted in advance from the City Council.