High-Capacity Magazine Laws by State
A high-capacity magazine usually means a detachable box magazine holding more than ten rounds. State laws also use terms such as large-capacity magazine, prohibited magazine and detachable magazine, so the legal definition must be checked before buying or shipping.
There is no single nationwide magazine-capacity limit. Restrictions come from state statutes, licensing systems and local rules, and they may cover possession, purchase, manufacture, transfer, ammunition capacity or only certain firearm types.
This state-by-state overview maps the main rules for American buyers and Australian visitors. It is general information rather than legal advice; pending amendments, court orders and local ordinances can change the result.
Federal Rules and Magazine Definitions
The federal government does not impose a general maximum on detachable magazines. Federal background-check and dealer rules still apply to firearm transfers, while a state may prohibit a magazine even when its federal treatment is lawful.
A fixed-capacity firearm, such as a traditional revolver with a six-shot cylinder, is treated differently from a pistol fitted with a removable box magazine. Definitions also vary between semiautomatic pistols, rifles and shotguns, so the same magazine can be legal in one state and restricted in another.
States With Broad Capacity Limits
California, New Jersey, Hawaii and Washington, D.C. generally prohibit magazines above ten rounds. Narrow exemptions may apply to certain calibre firearms, law-enforcement users, licensed dealers or qualifying collectors, but ordinary buyers should assume a ten-round ceiling.
New York generally treats a magazine capable of holding more than ten rounds as a large-capacity magazine, with firearm-specific treatment for some eight-to-ten-round magazines. Permit and registration requirements can apply in addition to the capacity rule.
Massachusetts limits detachable magazines to ten rounds for semiautomatic rifles and shotguns and twenty rounds for semiautomatic pistols. Maryland uses a similar ten-round long-gun limit but permits twenty-round pistol magazines. Existing magazines may qualify for continuing possession under narrow grandfathering provisions.
Rules That Vary by Firearm Type
Connecticut prohibits detachable magazines over ten rounds for long guns and over seventeen rounds for pistols. Its assault-weapons definitions, certificate-of-possession rules and local requirements can add further restrictions, particularly for buyers without a valid permit.
Illinois generally caps semiautomatic rifles and shotguns at ten rounds and pistols at fifteen. Delaware similarly uses ten rounds for long guns and fifteen for pistols. Firearm-owner and dealer permits, fixed magazines and qualifying exceptions must be checked separately.
States Without a General Numeric Cap
Most other states have no general statewide numeric cap. This group comprises Alabama, Alaska, Arizona, Arkansas, Colorado, Florida, Georgia, Idaho, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Mexico, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin and Wyoming.
A free market in magazines does not mean an unrestricted purchase. Colorado, Michigan, Oregon, Pennsylvania and West Virginia, for example, use combinations of permits, background checks, registration or training requirements. Other states restrict particular semiautomatic weapons by features such as pistol grips, folding stocks or barrel lengths.
Retail references can help with model compatibility. Guns and Magz’s rifle selection guide identifies rifles that use detachable magazines, after which the manufacturer’s magazine chart should confirm fit and calibre.
Permits, Local Ordinances and Existing Magazines
A grandfathered magazine may remain lawful in the hands of its owner after a ban, yet be barred from sale, manufacture or new transfers. California and New York are well known for such distinctions, and other states may require registration, a permit or proof of lawful acquisition.
City and county ordinances can sometimes supplement state law, although state preemption and court rulings limit their reach. Permit-to-purchase rules may also change how a magazine and firearm are acquired. For collection records, the firearm serial-number guide explains the identifiers and year markings that can help document an existing gun.
Buying in the United States from Australia
Americans usually buy firearms through a licensed Federal Firearms Licensee, or FFL. Guns and Magz ships firearm purchases to FFL dealers nationwide, where the transfer process, identity checks, permits and destination-state rules are addressed. Buyers should confirm the magazine is lawful before ordering; a compliant firearm does not make a prohibited magazine lawful.
Australia uses a different system: the federal Firearms Act 1996 and state or territory licensing, supported by the National Firearms Register. Many jurisdictions limit detachable magazines to ten rounds. Purchases generally run through licensed dealers or tightly controlled transfers, and clubs and commercial ranges in Melbourne, Sydney and Brisbane are important parts of the local market.
US permit terminology can be confusing. Atlantic Green Cross provides firearms-training and permit-oriented resources, but an Australian visitor cannot rely on a US permit or dealer to satisfy Australian requirements. Customs is equally important: declare firearms and relevant components, obtain any required Australian Border Force permit, and secure temporary-export approval before taking a firearm or magazine overseas.
Compare State Approaches and Plan Ahead
Use this summary to identify the governing rule, then check the current statutory text and local requirements before committing to a purchase. For a firearm already in the United States, record its make, model, calibre, magazine type and capacity; for an overseas purchase, confirm import permission before payment and shipment.
| State or jurisdiction | General capacity rule | Main qualification |
|---|---|---|
| California, New Jersey, Hawaii, D.C. | Ten-round maximum | Narrow firearm, collector and law-enforcement exceptions |
| New York | Generally ten rounds | Firearm-specific treatment; registration and local permits |
| Massachusetts | Ten long-gun and 20 pistol rounds | Detachable magazines; limited exceptions |
| Maryland | Ten semiautomatic long-gun and 20 pistol rounds | Fixed magazines and qualifying exceptions |
| Connecticut | Ten long-gun and 17 pistol rounds | Permits and assault-weapon rules |
| Illinois | Ten semiautomatic long-gun and 15 pistol rounds | FOID and permit requirements |
| Delaware | Ten long-gun and 15 pistol rounds | Permit and qualifying exceptions |
| Remaining states | No general statewide numeric cap | Local, purchase and feature-based restrictions apply |
Before ordering a detachable magazine, have the dealer confirm the firearm, capacity, magazine type and destination-state eligibility in writing. Keep purchase records and any grandfathering evidence, and check whether a fixed-capacity firearm is a more practical legal option.
Contact the FFL dealer or the relevant state firearms authority for a current answer, then choose a compliant magazine that fits the exact firearm model. That verification step can prevent a costly return, transfer refusal or unlawful possession.