Commonwealth v. Cassidy, 96 N.E.3d 691

Background

Defendant, a Texas transplant to Massachusetts for law school, brought an AK-47–style pistol and a nine‑mm pistol (and magazines/ammunition) he had lawfully bought in Texas into his Massachusetts residence.
Police executed a search warrant March 2, 2011; officers recovered both pistols, four high‑capacity magazines (including a 30‑round AK magazine and an extended 15–20 round nine‑mm magazine), boxes of ammo, and loose rounds from the defendant’s bedroom.
Defendant admitted purchasing and transporting the guns from Texas and that he had not registered or licensed them in Massachusetts because he could not afford the fees.
Jury convicted him of unlawful possession of an assault weapon (G. L. c. 140, § 131M), unlawful possession of a large capacity firearm and four large capacity feeding devices (G. L. c. 269, § 10(m)), and unlawful possession of ammunition (G. L. c. 269, § 10(h)).
On appeal to the SJC the defendant argued (1) the Commonwealth failed to prove he knew the items were “large capacity,” (2) the statutes are unconstitutionally vague, and (3) the statutes violate the Second Amendment and art. 17 of the Massachusetts Declaration of Rights.

Issues

Issue	Plaintiff's Argument (Commonwealth)	Defendant's Argument (Cassidy)	Held
Mens rea for “large capacity” under G. L. c. 269, § 10(m)	"Knowingly" modifies possession and the object; Commonwealth must prove defendant knew he possessed the item and that it met the statutory large‑capacity definition or could hold >10 rounds.	Commonwealth failed to prove Cassidy knew the firearms/magazines were >10‑round capacity; Staples requires proof of knowledge of weapon characteristics.	Court: "knowingly" applies to the whole object; Commonwealth must prove either knowledge that the item met the statutory definition or knowledge it could hold >10 rounds. Jury instruction and proof here were adequate.
Sufficiency of evidence on knowledge	Circumstantial evidence (ownership, prior use, defendant’s statements about loading practices, visibly large magazines, expert testimony on capacities) suffices to infer knowledge.	No direct proof defendant knew capacities; his Texas ownership and unfamiliarity with MA law undermine inference.	Court: Viewing evidence in prosecution’s favor, a rational jury could infer Cassidy knew magazines/firearm held >10 rounds; convictions upheld.
Vagueness / due process	Statutes provide clear definitions (large capacity weapon/feed device); enforcement statistics alone don’t show unconstitutional arbitrariness.	Statutes are complex, vague, and enforced arbitrarily; people of ordinary intelligence cannot determine what is prohibited.	Court: Statutes not unconstitutionally vague; provisions give sufficient notice and limit enforcement discretion.
Second Amendment / art. 17 challenge	Regulatory scheme and assault‑weapon/large‑capacity limits are permissible; do not eliminate core self‑defense rights.	Statutes infringe individual right to bear arms under Second Amendment and art. 17.	Court: SJC follows Heller/McDonald line — right is not unlimited; assault‑weapon and magazine limits are consistent with the Constitution; challenge fails.

Key Cases Cited

Staples v. United States, 511 U.S. 600 (defendant’s knowledge of weapon characteristics may be required)
Flores‑Figueroa v. United States, 556 U.S. 646 (ordinary reading of "knowingly" applying to object/elements)
Jackson v. Virginia, 443 U.S. 307 (standard for sufficiency of the evidence review)
Commonwealth v. Latimore, 378 Mass. 671 (viewing evidence in light most favorable to Commonwealth)
Commonwealth v. O’Connell, 432 Mass. 657 (distinguishing mens rea requirements where statute lacks explicit "knowingly")
District of Columbia v. Heller, 554 U.S. 570 (Second Amendment protects individual right but not unlimited)
McDonald v. City of Chicago, 561 U.S. 742 (Second Amendment incorporated against the States)
United States v. Miller, 307 U.S. 174 (limits on weapons not tied to militia service may be upheld)