Penal Code § 32900 PC – California “Bump Stock” Laws

Under Penal Code § 32900 PC, California law makes it illegal to use, possess, manufacture or give away bump stocks. Also called multiburst trigger activators, bump stocks are gun accessories that increase the rate at which semiautomatic rifles fire.

The language of the code section reads as follows:

32900. Except as provided in Chapter 1 (commencing with Section 17700) of Division 2 of Title 2, any person in this state 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 multiburst trigger activator is punishable by imprisonment in a county jail not exceeding one year or imprisonment pursuant to subdivision (h) of Section 1170.

Penalties

Possessing, manufacturing, or lending someone a bump stock device is a “wobbler” offense in California law. It can be prosecuted as a misdemeanor or a felony at the prosecutor’s discretion.

• As a misdemeanor, the penalty for possession of a bump stock is up to one year in county jail.
• Felony possession of a bump stock in California can be punished by 18 months to three years in jail.

Legal Defenses

Legal defenses to Penal Code 32900 charges include:

• You were legally permitted to own the bump stock.
• You were taking the bump to law enforcement for destruction.
• You did not know the bump stock was in your possession.
• The bump stock belonged to someone else.
• The bump stock was found during an illegal search.
• There was police misconduct, such as a coerced confession or planted evidence.

To help you better understand bump stock laws, our attorneys will answer the following questions:

• 1. What are “bump stocks”?
• 2. Do reciprocating stocks convert guns into automatic weapons?
• 3. Aren’t multiburst trigger activators legal under federal law?
• 4. Are bump stocks legal in California?
• 5. Who may legally own a multiburst trigger activator?
• 6. What is the penalty for possessing a bump stock in California?
• 7. What are some legal defenses?
• 8. Does federal law prohibit bump stocks?

California Penal Code 16930 defines “bump stocks” – legally known as “multiburst trigger activators” – as either of the following:

• A device designed or redesigned to be attached to a semiautomatic firearm, which allows the firearm to discharge two or more shots in a burst by activating the device; or
• A manual or power-driven trigger activating device constructed and designed so that when attached to a semiautomatic firearm it increases the rate of fire of that firearm.

In plain English, a bump stock (a.k.a. bump fire stock or slide fire) is a type of firearm modification. It is an accessory that modifies a semiautomatic weapon so that it can fire shots continuously (“rapid fire”) as long you keep the rifle against your shoulder. It makes a semi-automatic rifle more like an automatic rifle.

The bump stock — also referred to as a “reciprocating stock” — takes the place of the gun’s “standard stock” (that is, the piece of a semiautomatic rifle that rests against your shoulder).

By holding down the trigger and placing pressure on the barrel of the gun, a gunman using a bump stock can shoot almost as quickly as an automatic firearm.

Bump stocks were used during the Las Vegas mass shooting on October 1, 2017, which resulted in the death of 58 victims. As a result of using bump stocks, the shooter was able to fire approximately 90 in just 10 seconds.

2. Do reciprocating stocks convert guns into automatic weapons?

Technically, no. Bump stocks do not convert semi-automatic guns to automatic ones, even though they allow semiautomatic rifles to be fired almost as automatically.

3. Aren’t multi-burst trigger activators legal under federal law?

Federal law prohibits possession of any “machine gun” (that is, a fully automatic weapon) manufactured after May 19, 1986. Under federal law, a “machine gun” is defined as:

“any weapon which shoots, is designed to shoot, or can be readily restored to shoot, automatically more than one shot, without manual reloading, by a single function of the trigger.” ¹

On June 14, 2024, bump stocks are no longer considered machine guns under federal law.²

 4. Are bump stocks legal in California?

California Penal Code 32900 makes it illegal to possess, manufacture, import or sell a bump stock in California. Bump stocks have been illegal in California since 1990.³

Specifically, California Penal Code 32900 provides:

“Except as provided in Chapter 1 (commencing with Section 17700) of Division 2 of Title 2, any person in this state 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 multiburst trigger activator is punishable by imprisonment in a county jail not exceeding one year or imprisonment pursuant to subdivision (h) of Section 1170.”

5. Who may legally own a multiburst trigger activator?

People who may legally possess a bump stock in California include:

• Historical societies and museums;
• Authorized participants in a movie, television show, or video production;
• People who sell or rent bump stocks to museums or entertainment productions; and
• Law enforcement personnel.⁴

Such use is subject to obtaining permission, where applicable, and to such possession being otherwise in compliance with applicable law.

6. What is the penalty for possessing a bump stock in California?

Possession of a bump stock is a California “wobbler” offense. That means it can be prosecuted as either a California misdemeanor or a California felony, at the prosecutor’s discretion.

If prosecuted as a misdemeanor, possession of a bump stock can be punished by up to one (1) year in county jail.

As a felony, possessing a bump stock can result in a jail sentence of:

• 18 months,
• Two (2) years, or
• Three (3) years.⁵

For further information, please see our article on Felony Sentencing in California.

Note additionally, that regardless of whether the offense is prosecuted as a misdemeanor or a felony, a multiburst trigger activator can be confiscated as a nuisance by the California Attorney General.⁶

7. What are some legal defenses?

The best defense to charges of modifying a firearm with an illegal bump stock will depend on the specific facts of the case.

The following, however, are some of the most common defenses to bump stock charges under Penal Code 32990:

• You were legally permitted to own the bump stock.
• You were taking the bump stock to law enforcement for the authorities to dispose of.⁷
• You did not know the bump stock was in your possession.
• The bump stock belonged to someone else.
• The bump stock was found during an illegal search and seizure.
• There was police misconduct, such as a coerced confession or planted evidence.

Note that bump stocks can be lawfully possessed by certain museums, historical societies, authorized persons in movie or TV production crews, or police.

8. Does federal law prohibit bump stocks?

No. There was a federal ban on bump stocks that existed since March 26, 2019, but it was struck down by a a federal Appeals Court in New Orleans on January 6, 2023. Then on June 14, 2024, the U.S. Supreme Court overturned the ban.

The original ban by the federal government was prompted by the October 1, 2017 Las Vegas shooting. On December 18, 2018, Acting Attorney General Matthew Whitaker signed a regulation defining bump stocks as machine guns, which are illegal. This regulation took effect on March 26, 2019, 90 days after it was published in the Federal Register.

While the ban was ongoing, bump stock owners needed to destroy them or surrender them to the ATF. Possessing a bump stock used to carry:

• up to 10 years in Federal Prison, and/or
• a fine of up to $250,000⁸

Helpful Links:

• Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF)
• National Rifle Association (NRA)

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