California Penal Code Section 33600[1] provides that any person in California who manufactures or causes to be manufactured, imports into the state, keeps for sale, or offers or exposes for sale, or who gives, lends, or possesses any zip gun is guilty of a public offense. The statute covers the full lifecycle of zip gun activity -- from manufacturing through possession -- ensuring that no stage of creation, distribution, or ownership falls outside the prohibition.
Definition of Zip Gun
The term "zip gun" is defined in Penal Code Section 17360.[2] A zip gun is any weapon or device that meets all four of the following criteria simultaneously:
1. Not lawfully imported: The weapon was not imported as a firearm by an importer licensed pursuant to Chapter 44 (commencing with Section 921) of Title 18 of the United States Code
2. Not lawfully manufactured: The weapon was not originally designed to be a firearm by a manufacturer licensed pursuant to Chapter 44 of Title 18 of the United States Code
3. No excise tax paid: No tax was paid on the weapon, nor was an exemption from paying tax on the weapon granted, under Section 4181 and Subchapters F and G of Chapter 32 of Title 26 of the United States Code
4. Capable of firing a projectile: The weapon is made or altered to expel a projectile by the force of an explosion or other form of combustion
All four criteria must be satisfied for a device to qualify as a zip gun under this definition. The term historically refers to crude, homemade firearms constructed from pipe fittings, springs, rubber bands, and other hardware store materials. Unlike commercially manufactured firearms, zip guns are typically single-shot, unreliable, and lack the precision engineering and safety features of factory-produced weapons.
Interaction with Ghost Gun Laws (PC 29180)
California now addresses unserialized and privately manufactured firearms through separate statutory provisions. Penal Code Sections 29180 through 29184[3] require that all firearms manufactured or assembled in California -- including those built from unfinished frames or receivers, 3D-printed components, or other precursor parts -- bear a DOJ-issued serial number. The deadline for existing owners to apply for serial numbers was January 1, 2024, and new residents must apply within 60 days of establishing residency.
The zip gun statute (PC 33600) and the ghost gun framework (PC 29180) target different categories of prohibited weapons. A privately manufactured firearm built from an 80% lower receiver may violate PC 29180 if it lacks a DOJ-issued serial number, but it would not typically qualify as a zip gun under the PC 17360 definition unless all four criteria are met. Conversely, a crude improvised weapon assembled from non-firearm parts that meets all four criteria of Section 17360 is a zip gun regardless of whether the ghost gun serialization requirements also apply. In practice, a device could violate both statutes simultaneously.
Distinction from Multiburst Trigger Activators
Zip guns should not be confused with multiburst trigger activators, which are governed by a separate statute at Penal Code Section 32900.[4] Section 32900 prohibits devices that, when attached to a semiautomatic firearm, increase its rate of fire. These are entirely different categories of prohibited items.
Penalties
A violation of Section 33600 is punishable by imprisonment in a county jail not exceeding one year, or by imprisonment pursuant to subdivision (h) of Section 1170 (state prison).[1] The offense is a wobbler, meaning prosecutors have discretion to charge it as either a misdemeanor (county jail) or a felony (state prison). Additional charges may apply if the zip gun is used in the commission of another crime or is possessed by a person prohibited from possessing firearms.