Possession of an Assault Weapon (Penal Code Section 30605)

California has some of the nation’s strictest laws on semiautomatic rifles and other so‑called “assault weapons.” Possessing one without proper registration can lead to a felony conviction. As a firm that routinely handles firearms cases across Southern California, Radford & Rome, LLP understands the technical details of these laws and how prosecutors attempt to prove them. This article explains the crime of possessing an assault weapon, the statutory definitions that determine what qualifies as an “assault weapon,” common penalties and defenses, and how owners modify rifles to remain compliant under California law.

What Is an “Assault Weapon” in California?

Penal Code § 30605 makes it a crime to possess an assault weapon, but it does not define the term. Instead, California cross‑references several statutes and regulations:

Penal Code § 30515. This section lists firearm configurations that qualify as assault weapons. Examples include a semiautomatic centerfire rifle with a fixed magazine that holds more than 10 rounds or a semiautomatic rifle with an overall length under 30 inches.
Specific features. The Department of Justice regulations define prohibited features. A “pistol grip that protrudes conspicuously beneath the action,” a thumbhole stock, a flash suppressor, or a forward pistol grip all count as assault‑weapon characteristics. A firearm with one of these features and a detachable magazine is classified as an assault weapon.
Listed models. Some makes and models are designated assault weapons by name under Penal Code § 30510 (e.g., certain AK‑ and AR‑type rifles).

Feature‑Based Definitions

The law treats semiautomatic rifles, pistols and shotguns differently, but all share the same concept: a semiautomatic firearm with a detachable magazine and at least one prohibited feature is an assault weapon. Prohibited features include:

Pistol grip: any grip that allows the web of the trigger hand to be placed below the top of the trigger while firing.
Thumbhole stock: a rifle or shotgun stock with a hole that allows the shooter’s thumb to penetrate or wrap through the stock.
Flash suppressor: a device attached to the muzzle that reduces or redirects muzzle flash.
Forward pistol grip: a grip forward of the trigger for the non‑trigger hand.
Grenade launcher or flare launcher, folding or telescoping stock, or a second handgrip, among others (see PC 30515 for more specific details about what constitutes an assault weapon feature).

If a semiautomatic centerfire rifle has a fixed magazine (one that cannot be removed without disassembling the action) it is an assault weapon when it holds more than ten rounds. A shotgun with a revolving cylinder is also an assault weapon under the statute.

Pistols and Shotguns

The assault‑weapon definition extends beyond rifles. Semiautomatic pistols with detachable magazines become assault weapons if they exhibit any of the following characteristics:

Threaded barrel. A barrel capable of accepting a flash suppressor or handgrip.
Second handgrip or forward handgrip. Pistols that allow the support hand to grasp the gun ahead of the trigger.
Barrel shroud. A covering that enables the shooter to hold the barrel without burns.
Magazine located outside the pistol grip. If the magazine well sits anywhere other than the grip.
Fixed magazine over ten rounds. Semiautomatic pistols with fixed magazines that hold more than ten rounds.

For semiautomatic shotguns, the law singles out features such as a folding or telescoping stock or a revolving cylinder. Any semiautomatic shotgun with these features, or with the capacity to accept a detachable magazine, generally qualifies as an assault weapon unless it is featureless and otherwise compliant. Traditional hunting shotguns with tubular magazines and no pistol grips are generally lawful so long as they lack these assault‑weapon characteristics.

AR‑Style Pistols and the Handgun Roster

AR‑platform pistols—compact firearms built on AR‑15‑style receivers—present unique issues. Because they are considered semiautomatic pistols, they are subject to California’s Unsafe Handgun Act, which requires handguns sold by dealers to appear on the Roster of Handguns Certified for Sale. A notable exception is the single‑shot AR pistol (often referred to as SSE or Single-Shot-Exempt). A single‑shot AR pistol fires only one round before needing to be reloaded and typically uses a sled instead of a magazine. Because it is single‑shot, it is exempt from the roster requirement. After purchase, converting a single‑shot AR pistol back to a semiautomatic firearm with a detachable magazine can transform it into an unregistered assault weapon. Anyone considering such modifications should consult knowledgeable counsel, as doing so could potentially lead to felony charges.

What Does “Featureless” Mean?

California regulations define “featureless” as a semiautomatic firearm lacking the characteristics associated with assault weapons. In practical terms, a featureless build is a rifle, pistol or shotgun that retains its semiautomatic function but removes the prohibited features.

For rifles, owners often replace the pistol grip with a “fin” or “spur” grip that prevents the hand from wrapping around the grip, install a fixed or pinned stock instead of a folding/telescoping stock, and attach a muzzle brake or compensator rather than a flash suppressor.

For pistols, there are fewer options, but compliance generally requires removing any threaded barrel or forward handgrip and ensuring that the magazine inserts into the pistol grip. Many AR‑style pistols remain compliant only in single‑shot form with a fixed sled rather than a detachable magazine.

For shotguns, a featureless configuration typically means using a traditional fixed stock, avoiding pistol grips, and ensuring the shotgun has a fixed tubular magazine rather than a detachable magazine or revolving cylinder.

Because a featureless firearm lacks the prohibited features, it avoids classification as an assault weapon even if it has a detachable magazine. However, owners must still comply with other firearms laws, including magazine‑capacity limits and registration requirements.

“Fixed Magazine” and Bullet‑Button Rifles

The regulations also define fixed magazine as an ammunition feeding device that cannot be removed without disassembling the firearm’s action. Prior to 2017 many Californians used bullet‑button devices—magazine releases that could only be activated with a tool—to comply with the fixed‑magazine requirement. The law now states that a bullet button does not create a fixed magazine; rifles equipped with bullet buttons and a prohibited feature are considered assault weapons and must have been registered or modified.

Elements of Possession of an Assault Weapon in California (P.C. 30605):

To convict someone under Penal Code § 30605, the prosecution must prove beyond a reasonable doubt that:

The defendant possessed an assault weapon. Possession can be actual (direct physical control) or constructive (the ability to exercise control over the firearm).
The weapon met the statutory definition of an assault weapon. This may require expert testimony or forensic evidence showing the weapon’s features and magazine capacity.
The possession was unlawful. People with valid permits to possess assault weapons (e.g., law enforcement or individuals who properly registered their firearms before the cutoff) are exempt.

Penalties

Possessing an assault weapon is a wobbler: prosecutors can charge it as either a misdemeanor or a felony. Under Penal Code § 30605(a)–(b):

Misdemeanor: up to one year in county jail and a fine of up to $1,000.
Felony: 16 months, two years, or three years in county jail.
Infraction: in limited circumstances, a first‑time offender who lawfully possessed and then relinquishes an assault weapon may be fined up to $500.

The firearm will likely be seized and destroyed after the resolution of a case like this.

Defenses

Several defenses may apply:

Registration or permit. Proof that you lawfully registered the weapon before California’s deadlines or possess a valid assault‑weapon permit can defeat the charge.
Not an assault weapon. Expert examination may show the firearm does not meet the criteria under PC 30515 or that it was featureless and compliant.
Lack of possession. The prosecution must prove you had control over the firearm. Showing that you did not control the weapon (for example, it belonged to someone else at whose house you were staying) can be a defense.
Unlawful search and seizure. Evidence obtained through an illegal search may be suppressed, potentially leading to dismissal.

Possession of an assault weapon often overlaps with other firearm offenses:

Manufacturing or selling an assault weapon (PC 30600): prohibits making or transferring assault weapons and carries heavier penalties.
Possession of destructive devices (PC 18710/18720): bans bombs, grenades and explosives and is a wobbler or felony depending on the materials involved.
Possession of a .50 BMG rifle (PC 30610): criminalizes possession of certain large‑caliber rifles.
Felon in possession of a firearm (PC 29800) and ammunition possession (PC 30305): prohibit possession of firearms or ammunition by convicted felons; see our related articles for details.

Why You Need Skilled Counsel

Possessing a rifle with the wrong combination of features can turn a lawful firearm into a felony. Determining whether a gun is an “assault weapon” often requires detailed knowledge of overlapping statutes and regulations. Radford & Rome, LLP has extensive experience with California firearms law. We work with firearms experts to analyze the technical characteristics of a weapon, challenge illegal searches and negotiate with prosecutors. If you have been charged with possessing an assault weapon—or need advice about making a firearm featureless and compliant—contact our office. We serve Los Angeles and the surrounding counties and are committed to securing the best possible outcome for our clients.