US gun law is a patchwork of federal statutes, state laws, and local ordinances that interact in non-obvious ways. The federal framework sets a floor — states can only add restrictions, never remove federal requirements. But the variation between states is enormous: what's legal in Arizona may be a felony in New Jersey.
This guide gives you the legal framework every gun owner needs. It is not legal advice — if you have specific questions about your situation, consult an attorney. But this is the foundational knowledge that keeps you out of accidental legal trouble.
Federal Law: The Gun Control Act and NFA
Two federal statutes govern civilian firearms in the United States:
The Gun Control Act of 1968 (GCA) — establishes the federal framework for firearms commerce. Key provisions: dealers must have an FFL (Federal Firearms License); buyers must be 18+ for rifles and shotguns, 21+ for handguns (from dealers); background checks via NICS are required for all FFL purchases; certain persons are prohibited from possessing firearms (felons, domestic violence convicts, illegal aliens, those adjudicated mentally defective, others).
The National Firearms Act of 1934 (NFA) — regulates a specific category of firearms: suppressors, short-barreled rifles (SBRs), short-barreled shotguns (SBSs), machine guns, and 'any other weapons' (AOWs). In January 2026, Congress eliminated the $200 NFA tax stamp requirement, making suppressor and SBR ownership significantly more accessible. The registration, background check, and ATF approval process remains.
The Firearm Owners Protection Act of 1986 (FOPA) — among other provisions, banned new civilian machine gun registrations after May 19, 1986. Pre-86 registered machine guns remain legal for civilians but are extremely expensive ($20,000–$100,000+) due to supply constraints. FOPA also established the Safe Passage provision — allowing interstate transport of firearms in a federally compliant manner.
Post-Bruen (2022 SCOTUS): The Supreme Court's Bruen decision established that firearm regulations must be consistent with historical tradition. This has been used to challenge numerous state restrictions, with ongoing litigation in 2026.
Prohibited Persons: Who Cannot Legally Own a Firearm
Under federal law, you are prohibited from possessing firearms if you:
Lying on ATF Form 4473 about any of these is a federal felony — 10 years in federal prison. The form is simple and designed to be answered honestly. Don't create a problem where none exists.
Note on marijuana: this is the most common area where otherwise law-abiding people create legal exposure. If you use marijuana (recreationally or medically) in any state, you are federally prohibited from possessing firearms. States cannot override federal prohibition status.
The State Variation: What Changes State to State
States can impose requirements beyond federal minimums. The major categories of state variation:
Assault Weapons Bans (AWBs) — California, New York, New Jersey, Maryland, Massachusetts, Connecticut, Hawaii, Illinois, and Washington restrict certain semi-automatic rifles based on cosmetic features (pistol grips, adjustable stocks, flash hiders). The definitions vary by state. What's legal in Texas is illegal in California.
Magazine capacity limits — California (10 rounds), New York (10 rounds), Maryland (10 rounds), Colorado (15 rounds), and others restrict magazine capacity. Existing standard-capacity magazines are sometimes grandfathered; sometimes not. Know your state's current law — it changes frequently through legislation and court decisions.
Waiting periods — California, Florida, Washington, and others impose waiting periods between purchase and transfer (Washington: 10 business days for all firearms; California: 10 days; Florida: 3 days for handguns). NICS approval does not start your clock — it begins at time of purchase.
Permit-to-purchase — some states require a permit before you can buy a firearm, separate from the carry permit. Illinois (FOID card), Hawaii, New Jersey, Massachusetts, and others.
Red Flag Laws (Extreme Risk Protection Orders) — 22 states allow courts to temporarily remove firearms from individuals deemed a risk to themselves or others, with varying due process protections. Post-Bruen challenges are ongoing in multiple states.
Interstate Transport: The Safe Passage Rules
Traveling with firearms across state lines? The Firearm Owners Protection Act's Safe Passage provision (18 U.S.C. § 926A) provides federal protection for interstate transport IF:
The key danger: traveling through anti-gun states with legal firearms. New Jersey, New York, and Maryland have prosecuted travelers claiming Safe Passage. The law exists but exercising it means potential arrest and a long legal battle. The practical advice: know every state's law before transporting firearms through it, and avoid overnight stops in restrictive states with your firearms in the vehicle if possible.
Flying with firearms is fully legal under TSA rules: unloaded in a hard-sided locked case, declared at check-in, in checked baggage. Airlines have minor variations — always check the specific airline's policy before flying.
DJ Cavalcanti is the founder of DownRange, America's Firearms Intelligence Hub. A lifelong 2A advocate and Washington State resident, he built DownRange to give every American gun owner access to the legal intelligence and practical knowledge they need — all in one place.