Can You Have an Adjustable Stock in California?

An adjustable stock is legal in California on a semi-automatic rifle only when the rest of the rifle is configured to stay outside the state’s assault weapon definition. On a centerfire rifle, that means either installing a fixed magazine or stripping every other restricted feature. On a rimfire rifle, the feature rules don’t apply at all, so a telescoping stock is fine on its own.

Why the Stock Alone Isn’t the Question

California Penal Code 30515 does not ban folding or telescoping stocks outright. It bans a specific combination: a semi-automatic centerfire rifle that has a detachable magazine and any one feature from a short list. A telescoping or folding stock is on that list, alongside a pistol grip, a thumbhole stock, a flash suppressor, a forward pistol grip, and a grenade or flare launcher.¹

One feature is enough. A detachable-magazine AR with a standard collapsible stock on the buffer tube is already an assault weapon under the statute, even if nothing else about it is “tactical.” California’s regulations spell this out directly, defining a telescoping stock as one whose sections slide into each other and naming the AR-15 buffer tube as the fixed portion on which the buttstock slides.²

So the real question isn’t whether you can own an adjustable stock. It’s which of two legal paths you want to use to keep it.

Option 1: Fixed Magazine, Keep the Adjustable Stock

The feature list in Penal Code 30515 applies only to centerfire rifles without a fixed magazine. Install a properly fixed magazine, and the rifle can legally wear every feature on the restricted list, including a telescoping or folding stock.¹

California defines a fixed magazine as a feeding device that cannot be removed without disassembling the firearm action.² On an AR platform, that typically means the upper and lower receivers have to separate before the magazine will drop. Aftermarket kits accomplish this by forcing the user to pull the rear takedown pin and break the action open before the mag release will function. These usually run between $35 and $50.

Two numbers still apply on this path. The fixed magazine cannot exceed 10 rounds; California prohibits any feeding device that accepts more than ten.³ And the rifle must measure at least 30 inches in overall length.¹ If your stock is pinned extended, measure that way; if it still collapses because you’ve gone the fixed-magazine route, measure fully collapsed to confirm you clear 30 inches at the shortest setting.

The tradeoff is reload speed. Every magazine change requires opening the action. For range shooting and most recreational use, that’s minor. For competitive shooters, it can be a dealbreaker.

Option 2: Featureless Build, Pin the Stock

The other path keeps the detachable magazine and removes every restricted feature, including the ability of the stock to adjust. No telescoping stock, no pistol grip, no thumbhole stock, no flash suppressor, no forward grip. A compliant rifle in this configuration falls outside the assault weapon definition entirely.

Many owners replace the collapsible stock with an aftermarket fixed stock built for California compliance. Others keep the original stock and pin it in a single position. The common method is to drill through the stock body and into the buffer tube, then seat a roll pin that blocks all movement. A “blind pin” that penetrates only the first wall of the buffer tube is preferred, because a through-pin can be pushed out from the opposite side, and a stock that can be returned to adjustable condition without a tool reads as still telescoping. Epoxy over the pin is common for extra permanence.

Products also exist that lock the stock without drilling, either by replacing the adjustment lever with a locked version or by blocking the slide with a polymer insert. The legal standard is the same regardless of method: the stock must require a tool to change position or be permanently secured. If you can collapse or extend it by hand, California still treats it as telescoping.

Going featureless also requires a compliant grip. California’s regulations treat a grip as a pistol grip when it allows the web of the shooter’s hand to drop below the top of the trigger during firing.² A compliant grip prevents that drop.

If any of this is uncertain on your specific rifle, a gunsmith experienced with California compliance can do the work and confirm it meets the standard.

Rimfire Rifles Are Outside the Rules

The entire feature framework in Penal Code 30515 applies to centerfire semi-automatic rifles only. Rimfire rifles, including .22 Long Rifle and .17 HMR, are not covered.¹

A rimfire semi-auto can legally run a telescoping stock, a pistol grip, a detachable magazine, and a flash suppressor at the same time without becoming an assault weapon. The distinction is the cartridge’s ignition method, not the rifle’s appearance. This is why platforms like the Ruger 10/22 are common choices for shooters who want a modern adjustable setup without compliance modifications. Standard firearm laws, the 10-round magazine cap, and overall length requirements still apply.

Semi-Automatic Shotguns Follow a Different Standard

If your question is actually about a shotgun rather than a rifle, the trigger is different. A semi-automatic shotgun becomes an assault weapon only when it has both a folding or telescoping stock and a pistol grip, thumbhole stock, or vertical handgrip.¹ A collapsible stock with a traditional stock grip is fine on its own. Pump and bolt-action shotguns are not covered at all.

Barrel and Overall Length Still Matter

Two length rules apply regardless of which path you take. A semi-automatic centerfire rifle with an overall length under 30 inches is an assault weapon in California, period.¹ Overall length is measured along a line parallel to the bore from the rearmost point of the firearm to the muzzle.

Separately, Penal Code 33215 prohibits civilians from possessing short-barreled rifles, which California defines as rifles with barrels under 16 inches. California does not recognize the federal NFA registration path for civilian SBR ownership. A barrel under 16 inches makes the rifle illegal under a separate statute no matter how the stock and magazine are configured.

What Happens If You Get It Wrong

Possessing an unregistered assault weapon is a wobbler under Penal Code 30605. Prosecutors can charge it as a misdemeanor, carrying up to one year in county jail, or as a felony, carrying 16 months, two years, or three years under California’s realignment sentencing structure.⁴ A felony conviction triggers a lifetime firearms prohibition under both state and federal law.

What makes these penalties worth taking seriously is how narrow the line is. The difference between a legal rifle and a felony can be whether a pin is properly seated in a buffer tube, or whether a magazine lock actually forces the action open before the magazine releases. If you’re not sure your configuration qualifies, don’t take the rifle to a range or transport it until a qualified gunsmith has looked at it.

1
State of California – Department of Justice – Office of the Attorney General. Assault Weapons Laws (California and Federal Law)
2
Cornell Law School. Cal. Code Regs. Tit. 11, 5471 – Registration of Assault Weapons
3
California Legislative Information. California Penal Code PEN 32310
4
California Legislative Information. California Penal Code PEN 30605