United States v. Simmons: Limiting the Firearm-Counting Rule in §2K2.1(b) — Non-NFA Weapons Are Irrelevant Unless Tied to the NFA Offense

Introduction

In United States v. Stephen Simmons, No. 23-4607 (4th Cir. July 7, 2025), the Fourth Circuit vacated a 36-month sentence imposed on a defendant who pled guilty to possessing an unregistered “auto sear” (a machine-gun conversion device) in violation of the National Firearms Act (NFA). Although the court rejected Simmons’s Second Amendment and vagueness challenges, it held that the district court had misapplied two key sentencing enhancements under U.S.S.G. § 2K2.1. The opinion, authored by Judge Berner, clarifies how “relevant conduct” limits firearm-counting under § 2K2.1(b)(1) (“number of firearms”) and § 2K2.1(b)(4)(A) (“stolen firearm”), establishing that weapons outside the NFA are not automatically relevant to an NFA conviction and therefore cannot be used to increase sentencing ranges unless the government proves a factual nexus.

The decision re-emphasises that (i) a sentencing court must rigorously apply the “relevant conduct” criteria of § 1B1.3 before counting firearms, and (ii) erroneous Guidelines calculations generally require resentencing even when the imposed sentence falls within the correct range. Practitioners must therefore pay close attention to the analytical steps Simmons demands.

Summary of the Judgment

Second Amendment & Vagueness Challenges Rejected. Simmons could not invoke the Second Amendment because auto sears and silencers are “dangerous and unusual” weapons outside constitutional protection; and he lacked standing to attack § 922(g)(3)’s “unlawful user” language as vague because his own drug use was undisputed.
Error in Applying § 2K2.1(b)(1) (Number of Firearms). The district court counted 43 firearms (33 ordinary guns + 10 NFA devices). The Fourth Circuit held that only the 10 NFA devices related to the offense; the other 33 were irrelevant because their unlawful possession (as a drug user) was not part of the same scheme or episode as possessing an unregistered auto sear.
Error in Applying § 2K2.1(b)(4)(A) (Stolen Firearm). The stolen weapon was a non-NFA firearm unrelated to the unregistered auto sear offense; therefore the two-point enhancement was improper.
Harmless-Error Argument Rejected. Even though the 36-month sentence fits inside the recalculated 30-37-month range, Molina-Martinez dictates resentencing because the Guidelines are the sentencing “starting point.”
Disposition. Sentence vacated and case remanded for resentencing; constitutional claims dismissed.

Analysis

Precedents Cited and Their Influence

District of Columbia v. Heller, 554 U.S. 570 (2008) and United States v. Miller, 307 U.S. 174 (1939) — Provided the baseline distinction between arms “in common use for lawful purposes” and “dangerous and unusual weapons.” The court used these to exclude auto sears (machine-gun parts) and silencers from Second-Amendment coverage.
N.Y. State Rifle & Pistol Ass’n v. Bruen, 597 U.S. 1 (2022) — Guided Simmons’s Bruen-style challenge, but the court avoided deep historical analysis by relying on Simmons’s concession that NFA devices lack protection.
United States v. Myers, 553 F.3d 328 (4th Cir. 2009) — Critical for the rule that Guidelines definitions are frozen as of promulgation; even if § 922(g) were later struck down, the incorporated definition in § 2K2.1(a)(4)(B) would remain.
United States v. Claybrooks, 90 F.4th 248 (4th Cir. 2024) — Applied to bar Simmons’s vagueness claim where defendant’s conduct is clearly proscribed.
United States v. Vargem, 747 F.3d 724 (9th Cir. 2014) — Persuasive authority distinguishing between status-based gun crimes and NFA violations; cited in defining “same course of conduct” under § 1B1.3.
Other Guidelines cases: Cole (8th Cir.), Roxborough (6th Cir.), Gonzales (5th Cir.) — Established that stolen-firearm enhancement applies only if firearm is relevant to offense.
Molina-Martinez v. United States, 578 U.S. 189 (2016) — Provided harmless-error framework requiring resentencing when Guidelines miscalculated.

Legal Reasoning

Second Amendment Analysis
• The court bypassed the Bruen historical test because Simmons conceded that NFA devices (auto sears, silencers) are not constitutionally protected arms.
• Consequently, § 2K2.1(a)(4)(B)’s “prohibited person” enhancement did not burden protected conduct, ending the Second-Amendment inquiry.
• Even absent concession, precedent treats machine guns and silencers as “dangerous and unusual,” outside the Amendment.
Vagueness Challenge
• Under Claybrooks, a defendant whose conduct is unambiguously covered lacks standing to mount a vagueness attack. Simmons admitted recent methamphetamine and marijuana use, squarely within § 922(g)(3)’s reach.
Guidelines Misapplication
A. § 2K2.1(b)(1) Firearm Count
• Enhancements apply only to firearms that are both (i) unlawfully possessed and (ii) “relevant conduct” as defined by § 1B1.3.
• “Relevant conduct” demands a factual nexus—same course of conduct, common scheme, or single episode—considering similarity, regularity, and temporal proximity.
• The government produced no evidence linking Simmons’s status-based gun possession to the distinct act of possessing an unregistered auto sear; therefore only the 10 NFA items (the actual wrongdoing) count.

B. § 2K2.1(b)(4)(A) Stolen Firearm
• Same nexus test. The lone stolen, non-NFA firearm had no demonstrated connection to the NFA offense; enhancement unwarranted.
Harmless-Error Rebutted
• Following Molina-Martinez, an incorrect range presumptively affects the sentence. Government failed to show the district court would have imposed 36 months if it had started at 30-37 rather than 57-71 months.

Impact of the Judgment

1. “Relevant Conduct” Scrutiny Intensified. Practitioners must now anticipate strict appellate review when district courts mechanically include every firearm discovered at arrest. A separate, articulated analysis under § 1B1.3 is essential—particularly where the charge involves a narrow NFA violation but the search yields numerous ordinary guns.

2. Sentencing Consistency Across Circuits. Simmons aligns the Fourth Circuit with the Eighth, Sixth, and Fifth Circuits’ restrictive approach to the stolen-firearm enhancement. The ruling therefore reduces inter-circuit ambiguity and may nudge the Sentencing Commission toward clarifying commentary in § 2K2.1.

3. Second Amendment Litigation Strategy. The decision illustrates the limits of Bruen-style challenges in cases involving machine-guns, silencers, or other disfavoured weapons. Defense counsel must tailor constitutional arguments to firearms likely deemed “in common use.”

4. Guidelines-Error Presumption Remains Robust. Even within-range sentences are vulnerable when the district court’s starting point is wrong. That principle preserves the Guidelines’ centrality and gives defendants a meaningful remedy on appeal.

Complex Concepts Simplified

Auto Sear: A small metal or polymer part that, when installed in a semi-automatic firearm, converts it into a fully automatic machine gun. Under federal law, an auto sear itself is legally treated as a “machine gun.”
National Firearms Act (NFA): A 1934 statute imposing registration, taxation, and heightened regulation on certain weapons (machine guns, short-barrelled rifles/shotguns, silencers, destructive devices). Mere possession of an unregistered NFA weapon is a felony.
“Prohibited Person” (§ 922(g)): Categories of individuals barred from possessing firearms (e.g., felons, unlawful drug users, domestic-violence misdemeanants). The Guidelines import these categories to increase base offense levels.
Relevant Conduct (§ 1B1.3): The universe of acts a sentencing court may consider. Not every bad act counts—only those tied to the conviction by common scheme, temporal proximity, or similar purpose.
Harmless-Error Doctrine (sentencing): On appeal, a Guidelines miscalculation is harmless only if the reviewing court is certain the same sentence would have been imposed. After Molina-Martinez, certainty is rare.

Conclusion

United States v. Simmons reinforces two doctrinal pillars: the limited reach of the Second Amendment with respect to NFA weapons, and the demanding “relevant conduct” gateway for firearm-related enhancements under § 2K2.1. By vacating a sentence that—numerically—already fit within the correct range, the Fourth Circuit underscored the primacy of accurate Guidelines calculations and the importance of transparent judicial reasoning. Going forward, prosecutors must marshal concrete facts to link additional firearms to the charged conduct, while defense counsel have a strengthened basis to challenge over-inclusive counting. The opinion stands as a significant precedent for narrowing the practical scope of § 2K2.1(b) and for curbing the routine elevation of sentences through weapons that, although found nearby, are legally irrelevant to the crime of conviction.