Second Amendment “Common Use” Rule: Machineguns and Conversion Devices Fall Outside Constitutional Protection

Case: United States v. Maxon Alsenat (11th Cir.) Date: 2026-04-21 Statute: 18 U.S.C. § 922(o)(1)

1. Introduction

United States v. Maxon Alsenat presented a direct post-Bruen Second Amendment challenge to the federal machinegun ban, 18 U.S.C. § 922(o)(1), in the context of “machinegun conversion devices” (commonly understood as devices that enable automatic fire). A grand jury indicted Maxon Alsenat for knowingly possessing a “machinegun” by virtue of possessing such a conversion device, which the federal definitions treat as a machinegun. After the district court denied his motion to dismiss, Alsenat pleaded guilty and then appealed, arguing the statute is unconstitutional as applied to “adult citizen[s] who ha[ve] no felony convictions.”

The key issue was narrow but consequential: does the Second Amendment protect possession of machineguns (including conversion devices treated as machineguns by statute), such that § 922(o) cannot constitutionally be applied to a non-felon adult?

2. Summary of the Opinion

The Eleventh Circuit affirmed Alsenat’s conviction. The court held that machineguns are not protected by the Second Amendment because they are not “weapons in common use for lawful purposes” and fall within the historical tradition of prohibiting “dangerous and unusual weapons.” The panel also rejected the attempt to reframe the challenge as one limited to non-felons: because § 922(o) is constitutional as applied to Alsenat, his “quasi-facial” challenge necessarily failed.

3. Analysis

3.1 Precedents Cited

The opinion’s logic is built around a line of Supreme Court decisions defining (1) the scope of Second Amendment protection and (2) the procedural posture for challenging a statute after a guilty plea.

  • Class v. United States (2018): The court relied on Class for the proposition that a guilty plea does not, by itself, bar a defendant from challenging the constitutionality of the statute of conviction on direct appeal. This kept the door open for Alsenat’s Second Amendment claim notwithstanding his guilty plea.
  • United States v. Saac (11th Cir. 2011): Used to refine the Class principle—Alsenat’s challenge was cognizable because it could be resolved “by examining the face of the indictment or the record at the time of the plea” without further fact development and did not contradict his admissions.
  • United States v. Gruezo (11th Cir. 2023): Cited for the standard of review—constitutional challenges to criminal statutes are reviewed de novo.
  • District of Columbia v. Heller (2008): The centerpiece. The panel treated Heller as establishing a categorical boundary: the Second Amendment “does not protect those weapons not typically possessed by law-abiding citizens for lawful purposes,” supported by a historical tradition of prohibiting “dangerous and unusual weapons.” Critically, Heller itself signaled that bans on “M-16 rifles and the like” are permissible and called it “startling” to think machinegun restrictions might be unconstitutional.
  • N.Y. State Rif le & Pistol Ass'n v. Bruen (2022) and United States v. Rahimi (2024): The court used both to show continuity rather than disruption. In its telling, Bruen reaffirmed that the Second Amendment protects weapons “in common use” and not “dangerous and unusual” ones, and Rahimi reiterated that bans on “dangerous and unusual weapons” remain a recognized limitation.
  • Staples v. United States (1994), United States v. Freed (1971), and Haynes v. United States (1968): Though not Second Amendment holdings, these cases were deployed to characterize machineguns as a heavily regulated, quasi-suspect class of weapons tied to unlawful use (analogized to “hand grenades” in Freed and described in Haynes as weapons used principally by persons engaged in unlawful activities). The Eleventh Circuit leveraged this framing to reinforce that machineguns are not the kind of arms widely possessed for lawful purposes.
  • United States v. O'Brien (2010): Cited to underscore the “immense danger posed by machineguns,” supporting the court’s conclusion that automatic-fire weapons fit comfortably within the “dangerous and unusual” category.
  • McGuire v. Marshall (11th Cir. 2022), Doe v. Reed (2010), and United States v. Rahimi (2024): These cases structured the court’s treatment of Alsenat’s “as-applied to non-felons” claim as “quasi-facial.” Because the claim sought relief for a defined subset of persons covered by the statute (not merely Alsenat), the court required satisfaction of the demanding facial-challenge standard: the challenger must show “no set of circumstances exists under which” the law is constitutional. The opinion then short-circuited the claim: because the statute is constitutional as applied to Alsenat, the quasi-facial challenge fails.
  • Sister-circuit consensus: The panel expressly “join[ed]” other circuits holding that machineguns are outside Second Amendment protection, citing United States v. Morgan, United States v. Simmons, United States v. Bridges, United States v. One (1) Palmetto State Armory PA-15 Machinegun Receiver/Frame, Unknown Caliber Serial No. LW001804, United States v. Henry, United States v. Fincher, and also referencing Capen v. Campbell, United States v. Rush, and Hanson v. District of Columbia. This served an institutional function: presenting the Eleventh Circuit’s rule as consistent with an emerging post-Bruen equilibrium across the federal courts of appeals.

3.2 Legal Reasoning

The court’s reasoning is best understood as a two-step structure that mirrors how Heller is often operationalized even after Bruen:

  1. Threshold scope: The Second Amendment protects weapons “in common use” for lawful purposes, and historically permits bans on “dangerous and unusual weapons.” The court treated this as a categorical carve-out rather than a balancing test.
  2. Classification of machineguns: Machineguns (including conversion devices defined as machineguns) are not in common lawful use and are paradigmatically dangerous. The opinion reinforced this conclusion with:
    • Textual signals from Heller: machineguns (M-16 “and the like”) may be banned.
    • Functional character: automatic fire is “best suited for criminal purposes” rather than “the core lawful purpose of self-defense.”
    • Regulatory tradition and prevalence of bans: widespread state prohibitions beginning in the early 20th century, the 1934 National Firearms Act regime, and the 1986 enactment of § 922(o), plus present-day extensive regulation across jurisdictions.

Notably, the district court had offered an alternative rationale (that conversion devices, absent a separate firearm, are “accessories” or “accoutrements” rather than “Arms”). The Eleventh Circuit affirmed on the broader and more durable ground: machineguns themselves fall outside the Second Amendment’s protected class. That framing matters because it resolves not just the conversion-device posture, but the constitutionality of § 922(o) as a machinegun ban generally.

3.3 Impact

The opinion’s practical and doctrinal effects are significant within the Eleventh Circuit and beyond:

  • Post-Bruen stability for § 922(o): The decision reinforces that Bruen and Rahimi did not unsettle Heller’s “dangerous and unusual” limitation, anchoring machinegun bans as categorically permissible rather than subject to granular historical analogizing in each case.
  • Non-felon status is not a machinegun safe harbor: The court rejected the argument that a law-abiding adult’s status changes the analysis where the weapon class itself is unprotected.
  • Litigation posture—“quasi-facial” trapdoor: By characterizing “as applied to non-felons” as quasi-facial and importing the facial standard (no constitutional applications), the court makes subset-based challenges to categorical weapon bans harder to mount.
  • Convergence with other circuits: The opinion cements a multi-circuit consensus that machineguns are outside the Second Amendment. That consensus reduces the likelihood of successful forum-dependent challenges and increases the persuasive weight of the “common use” limitation for other weapon-category disputes.

4. Complex Concepts Simplified

“Weapons in common use for lawful purposes”: A shorthand from Heller—arms broadly possessed by law-abiding citizens for legitimate ends (especially self-defense). If a weapon is not commonly kept for lawful purposes, courts may treat it as outside the Second Amendment’s protective scope.

“Dangerous and unusual weapons”: A historically grounded category of arms that governments may prohibit. The phrase is used as a constitutional boundary: the more a weapon is both exceptionally dangerous and uncommon among law-abiding citizens, the easier it is to ban.

Machinegun conversion device: A device that enables a firearm to fire automatically; federal law can treat the device itself as a “machinegun,” meaning possession of the device alone can trigger § 922(o) liability.

As-applied vs. facial vs. “quasi-facial”:

  • As-applied: challenges the law only in the challenger’s specific circumstances.
  • Facial: argues the law is invalid in all its applications.
  • Quasi-facial (as used here): an “as-applied” claim aimed at a defined subset (e.g., all non-felon adults). The Eleventh Circuit treated this as triggering the demanding facial standard to the extent it extends beyond the appellant’s individual facts.

5. Conclusion

United States v. Maxon Alsenat establishes, for the Eleventh Circuit, a clear rule: machineguns are outside the Second Amendment’s protection because they are not in common lawful use and fit within the historically recognized category of “dangerous and unusual” weapons. The decision reads Bruen and Rahimi as reaffirming—not revising—Heller’s limitation, and it forecloses attempts to constitutionalize machinegun possession by focusing on the owner’s non-felon status rather than the weapon’s protected status. In doing so, it aligns the Eleventh Circuit with a growing appellate consensus sustaining § 922(o) against Second Amendment attack.