Morehouse Enterprises, LLC v. Bureau of ATF, 78 F.4th 1011

Plaintiffs: four "Private Plaintiffs" (one individual who makes firearms, one licensed dealer LLC, and two advocacy/legal organizations) and seventeen states challenged ATF’s April 26, 2022 Final Rule redefining "frame or receiver" (87 Fed. Reg. 24,652).
ATF promulgated the rule after notice-and-comment (proposed May 21, 2021; comment period closed Aug. 19, 2021); Final Rule effective Aug. 24, 2022.
Plaintiffs alleged the Final Rule exceeded statutory authority, violated the APA (lack of fair notice), created new serial-number/recordkeeping/registry obligations (violating 18 U.S.C. § 926), violated the Second Amendment, and was arbitrary and capricious.
District court denied a preliminary injunction; plaintiffs appealed. The Eighth Circuit reviewed the denial for abuse of discretion and affirmed.
The Eighth Circuit resolved the appeal on the preliminary-injunction showing of irreparable harm, finding plaintiffs’ alleged constitutional and economic injuries speculative and insufficient; it therefore did not reach merits.
The court noted that the States’ asserted harms were not addressed because the States lacked standing for those claims.

Issue	Plaintiff's Argument	Defendant's Argument	Held
APA / Notice-and-comment & fair notice	The Notice failed to give fair notice of the Final Rule’s scope and effects	ATF complied with notice-and-comment and adequately described proposed changes	Court did not reach merits because plaintiffs failed to show irreparable harm; injunction denied
Statutory authority / scope of "frame or receiver"	Rule impermissibly expands Gun Control Act’s scope by redefining regulated parts	ATF acted within delegated authority to clarify definitions in light of new technology	Merits not decided at PI stage; preliminary injunction denied for lack of irreparable harm
Recordkeeping/serial numbers / alleged national registry	Rule effectively creates a federal registry and new dealer obligations, violating §926	ATF says rule does not create a prohibited national registry or invalid recordkeeping scheme	Court did not decide merits; injunction denied for failure to demonstrate imminent, concrete harm
Irreparable harm (Second Amendment & economic) — PI-specific issue	Plaintiffs: Final Rule will burden Second Amendment rights and cause economic injury (compliance costs, closures, lost sales/tax revenue)	Government: Plaintiffs’ claimed constitutional and economic injuries are speculative, unquantified, and unlikely	Held: Plaintiffs failed to prove irreparable harm (claims too vague/speculative); district court not an abuse of discretion; preliminary injunction denied

MPAY Inc. v. Erie Custom Comput. Applications, Inc., 970 F.3d 1010 (8th Cir. 2020) (standard for preliminary injunction and abuse-of-discretion review)
Nebraska v. Biden, 52 F.4th 1044 (8th Cir. 2022) (preliminary-injunction status-quo principle)
Progressive Techs., Inc. v. Chaffin Holdings, Inc., 33 F.4th 481 (8th Cir. 2022) (extraordinary nature of preliminary injunctions)
Grasso Enters., LLC v. Express Scripts, Inc., 809 F.3d 1033 (8th Cir. 2016) (absence of irreparable harm alone defeats preliminary injunction)
Dakotans for Health v. Noem, 52 F.4th 381 (8th Cir. 2022) (irreparable-harm standard: certain, great, imminent)
Tumey v. Mycroft AI, Inc., 27 F.4th 657 (8th Cir. 2022) (harm must be likely, not a mere possibility)
Davis v. Fed. Election Comm’n, 554 U.S. 724 (2008) (standing: injury must be concrete, particularized, and traceable)
Powell v. Ryan, 855 F.3d 899 (8th Cir. 2017) (constitutional violations generally constitute irreparable harm)
Sessler v. City of Davenport, Iowa, 990 F.3d 1150 (8th Cir. 2021) (plaintiff must show irreparable injury is likely)
Packard Elevator v. I.C.C., 782 F.2d 112 (8th Cir. 1986) (injury must be actual and not theoretical for injunctive relief)
Sleep No. Corp. v. Young, 33 F.4th 1012 (8th Cir. 2022) (plaintiff’s burden to show irreparable injury likely)
Nken v. Holder, 556 U.S. 418 (2009) (balance of equities and public interest merge when government is opposing party)