Yes. Under Penal Code section 30605, possessing a firearm that meets California's legal definition of an assault weapon is itself a crime, no matter who owns it or whether that person has a clean record. This differs from a status-based charge such as felon in possession. Here, the gun's own features or model trigger the charge, unless a registration or other listed exception applies to that specific firearm.
What makes a firearm an assault weapon under California law
California defines "assault weapon" two different ways. Penal Code section 30510 lists specific makes and models by name. Penal Code section 30515 instead defines an assault weapon by features, so a firearm never named on the list in section 30510 can still qualify if it has the wrong combination of parts.
A semiautomatic, centerfire rifle that does not have a fixed magazine qualifies under section 30515 if it has any one listed feature, such as a pistol grip that protrudes conspicuously beneath the action, a thumbhole, folding, or telescoping stock, a flash suppressor, a forward pistol grip, or a grenade or flare launcher. A semiautomatic, centerfire rifle also qualifies if it has a fixed magazine that accepts more than 10 rounds or an overall length of less than 30 inches. A semiautomatic pistol without a fixed magazine qualifies with any one feature such as a threaded barrel capable of accepting a flash suppressor, forward handgrip, or silencer, a second handgrip, a barrel shroud, or the capacity to accept a detachable magazine outside the pistol grip, and a semiautomatic pistol with a fixed magazine that accepts more than 10 rounds also qualifies. A semiautomatic shotgun qualifies if it does not have a fixed magazine, or if it combines a folding or telescoping stock with a pistol grip, thumbhole stock, or vertical handgrip, and any shotgun with a revolving cylinder qualifies. A fixed magazine is one that cannot be removed without disassembling the firearm action. The statute also reaches other semiautomatic centerfire firearms that are not rifles, pistols, or shotguns under similar rules, and it excludes antique firearms and specified Olympic target pistols.
How this differs from felon in possession and other firearm charges
The firm's page on felon in possession of a firearm addresses a charge that depends on who the person is, such as a prior felony conviction or another prohibited status, applied to an otherwise ordinary firearm, and its broader page on unlawful possession of firearms covers that charge alongside concealed and loaded carry laws, with a short note on unregistered assault weapons. Section 30605 does not ask who you are. It asks what the gun is. A person with no criminal record at all can still be charged under section 30605 if the specific firearm they possess meets the statutory definition and no exception applies, and a status-based charge can also apply on top of this one if the person independently falls into a prohibited category for an unrelated reason.
Misdemeanor or felony: the penalty
A violation of section 30605 is a wobbler. The statute allows "imprisonment in a county jail for a period not exceeding one year, or by imprisonment pursuant to subdivision (h) of Section 1170." Under Penal Code section 1170(h), a felony that does not set its own term is punishable by 16 months, two years, or three years, ordinarily served in county jail. A narrower rule applies to some first violations: if the person was found with no more than two such firearms in compliance with Penal Code section 30945, proves they lawfully possessed the firearm before it was defined as an assault weapon, has no prior conviction under the same article of the law, was found in possession within one year after the end of the applicable registration period, and relinquishes the firearm for destruction, the violation is punishable by a fine of up to $500 instead.
Exceptions that can apply
The same article of the Penal Code lists several exemptions, including law enforcement agencies and the military for official duties under Penal Code section 30625, sworn peace officers of those agencies under section 30630, and, under section 30675, people acting under a Department of Justice permit and registered owners who possess an assault weapon as section 30945 allows. Registration itself was possible only within set periods. California has expanded the definition of assault weapon more than once and opened registration periods tied to those changes, but the deadlines in Penal Code section 30900 have all passed, the most recent requiring applications before January 1, 2022. None of these exceptions applies automatically. Each one depends on facts that usually have to be documented, such as a registration confirmation, a permit, or proof of the date the firearm was acquired, so do not assume an exception applies to a specific firearm without confirming the paperwork that actually supports it.
Common defenses
Because the charge turns on whether a specific firearm meets a technical legal definition, a defense often starts with an independent examination of the gun itself against the features listed in section 30515, or against the named models in section 30510. A firearm that meets none of the tests in section 30515 and is not a model named in section 30510, or a variation of a named rifle with only minor differences, is not an assault weapon under these definitions. The prosecution must also prove you knew or reasonably should have known the firearm had the characteristics that make it an assault weapon, as the California Supreme Court held in In re Jorge M. (2000) 23 Cal.4th 866, so how long you had a modified or inherited firearm and what you had reason to know about it can matter. A valid registration that law enforcement did not properly check, and the condition of a part the prosecution says makes the weapon restricted, are also areas worth examining with an attorney who can arrange for the firearm to be independently inspected.
What to do if you are under investigation or charged
Do not modify, sell, or dispose of the firearm once you know it is at issue in a case, since that can create a separate problem on top of the original charge. Locate any purchase records, registration confirmation, or documentation of when and how you acquired it, along with the make, model, and serial number as listed on any paperwork. The Law Offices of David S. Chesley can review the specific firearm and the paperwork with you.