Dangerous and Unusual Weapons

Historical Origin

English Common Law Foundation

The concept traces to English common law restrictions on carrying certain weapons:

"The offence of riding or going armed, with dangerous or unusual weapons, is a crime against the public peace, by terrifying the good people of the land."

— William Blackstone, Commentaries on the Laws of England (1769)

Early American Understanding

Colonial and state laws reflected similar principles:

• 1686 New Jersey: Prohibited concealed carry of "unusual and unlawful weapons"
• 1801 Tennessee: Banned carrying arms "to the terror of the people"
• 1813 Louisiana: Restricted carrying weapons "in a manner calculated to inspire terror"

19th Century Development

State courts elaborated the distinction:

"A man may carry a gun for any lawful purpose of business or amusement, but he cannot go about with that or any other dangerous weapon, to terrify and alarm, and in such manner as naturally will terrify and alarm a peaceful people."

— State v. Huntly, 25 N.C. 418, 422-23 (1843)

The Heller Framework

Supreme Court Recognition

DC v. Heller explicitly recognized this limitation:

"We also recognize another important limitation on the right to keep and carry arms. Miller said, as we have explained, that the sorts of weapons protected were those 'in common use at the time.' We think that limitation is fairly supported by the historical tradition of prohibiting the carrying of 'dangerous and unusual weapons.'"

— Justice Scalia, DC v. Heller, 554 U.S. 570, 627 (2008)

The Conjunctive Reading

Courts debate whether weapons must be both dangerous AND unusual:

• Conjunctive View: Weapon must be both dangerous and unusual to lose protection
• Disjunctive View: Either dangerous or unusual sufficient for prohibition
• Heller's Language: Suggests conjunctive ("dangerous and unusual")
• Practical Application: Most courts apply conjunctive test

Relationship to Common Use

The doctrines work together:

1. Weapons in common use are presumptively protected
2. Weapons both dangerous and unusual are not protected
3. All weapons are dangerous to some degree
4. Unusual danger plus unusual nature removes protection

Defining the Terms

"Dangerous"

Courts consider several factors in assessing danger:

"Unusual"

Unusual typically means:

• Not in common use: Rarely possessed by law-abiding citizens
• Not typically possessed: For lawful purposes
• Extraordinary nature: Beyond ordinary weapons for self-defense
• Historical anomaly: No tradition of civilian possession

Categories of Unprotected Weapons

Generally Recognized as Dangerous and Unusual

Disputed Categories

The Machine Gun Question

Historical Treatment

Machine guns represent the clearest application of the doctrine:

• 1934: National Firearms Act imposed registration and tax
• 1939: Miller didn't address machine guns directly
• 1968: Gun Control Act added regulations
• 1986: Hughes Amendment banned new civilian machine guns

Circuit Court Consensus

Federal circuits uniformly hold machine guns unprotected:

"We reject this argument because machine guns are 'dangerous and unusual weapons' that are unprotected by the Second Amendment."

— United States v. Henry, 688 F.3d 637, 640 (9th Cir. 2012)

The Circular Ban Problem

Critics note a circularity issue:

1. 1986 ban prevented machine guns from becoming common
2. Lack of common use justifies continued ban
3. Ban creates its own justification

Courts respond that:

• Machine guns were regulated before becoming uncommon
• Unusually dangerous nature justifies different treatment
• Military-civilian distinction has historical roots

NFA Weapons and the Doctrine

National Firearms Act Categories

The NFA regulates several weapon types as dangerous and unusual:

Post-Bruen Challenges

Recent challenges to NFA categories argue:

• No founding-era analogues for barrel length restrictions
• Suppressors have legitimate uses
• SBRs functionally similar to pistols with braces
• Text, history, tradition test requires reevaluation

Circuit Court Applications

Different Approaches

Circuits apply the doctrine differently:

Post-Bruen Uncertainty

Bruen's text, history, and tradition test creates new questions:

• Must find historical analogues for "dangerous and unusual" determinations
• Cannot use means-end scrutiny or balancing tests
• Focus shifts to founding-era understanding
• Modern technology challenges historical comparisons

Criticisms and Debates

Definitional Problems

Critics identify several issues:

1. Vagueness: No clear line between dangerous/unusual and protected
2. All Weapons Dangerous: Every weapon designed to be dangerous
3. Subjective Standards: "Unusual" depends on perspective
4. Moving Target: Technology and culture change over time

Constitutional Concerns

Policy Implications

Academic Perspectives

Joseph Blocher and Darrell A.H. Miller argue that the "dangerous and unusual" standard risks circularity: a prohibition that endures long enough can itself make a weapon unusual, and that unusualness then supplies the justification for the prohibition.

— Joseph Blocher & Darrell A.H. Miller, The Positive Second Amendment: Rights, Regulation, and the Future of Heller (Cambridge Univ. Press 2018)