Fixed Magazine Configurations Under California Law

California Penal Code Section 30515^[1] classifies a semiautomatic centerfire rifle as an assault weapon only if it has both a detachable magazine and a prohibited feature. By making the magazine non-detachable, a rifle may retain all features and remain compliant.

What Is a Fixed Magazine?

Under Penal Code Section 30515 and the implementing regulations in 11 CCR 5471^[2], a "fixed magazine" is an ammunition feeding device contained in, or permanently attached to, a firearm in such a manner that the device cannot be removed without disassembly of the firearm action. "Disassembly of the firearm action" means the fire control assembly is detached from the action in such a way that the action has been interrupted and will not function.

History: The Bullet Button Era (2007-2016)

From 2007 to 2016, California law defined "detachable magazine" as one that could be removed without the use of a tool. The Bullet Button, invented by Darin Prince, replaced the standard AR-15 magazine release with a recessed button that required a tool (typically the tip of a bullet) to depress. Under the pre-2017 detachable-magazine definition, a tool-operated release allowed a rifle to retain features such as a pistol grip, provided the rifle did not qualify as an assault weapon under another provision.

In 2016, SB 880 and AB 1135 defined "fixed magazine" as a device that cannot be removed without disassembly of the firearm action and classified semiautomatic centerfire rifles without a fixed magazine as assault weapons if they have a listed feature. Owners of eligible Bullet Button assault weapons were required to register them with the Department of Justice by June 30, 2018.

Current Fixed Magazine Solutions

After the Bullet Button was rendered non-compliant, the firearms industry developed several alternative fixed magazine systems:

• AR MagLock + Kingpin: Locks the magazine in place when the upper and lower receivers are closed. When the rear takedown pin (replaced by a Kingpin) is pulled, the upper pivots open, releasing the magazine. This satisfies the "disassembly of the action" requirement because the fire control group separates from the upper receiver.
• CompMag: A magazine body that is permanently fixed inside the rifle and loaded from the top through the ejection port. The CompMag cannot be removed without tools and disassembly.
• Hellfighter kit: Similar in concept to the AR MagLock system, it requires the action to be partially separated before the magazine can be released.
• Mean Arms MA Loader: Technically a fixed magazine solution combined with a top-loading stripper clip system that allows reloading through the ejection port without separating the action.

Advantages and Disadvantages

The fixed magazine approach allows retention of all ergonomic features, including the pistol grip, adjustable stock, and flash suppressor. The tradeoff is significantly slower reloading. With most fixed magazine systems, the shooter must partially separate the upper and lower receivers, drop the magazine, insert a new magazine, and close the action. This process is slower and more complex than a standard magazine change, which raises practical concerns for self-defense use.