Third Circuit Rule: A Single Illegible Serial Number Triggers § 2K2.1(b)(4)(B)(i) Even If Another Serial Number Is Legible

I. Introduction

This appeal concerns the scope of a federal sentencing enhancement aimed at firearms whose serial numbers have been tampered with. Noah Craddock, a convicted felon, pleaded guilty to unlawful possession of a firearm under 18 U.S.C. § 922(g)(1). The firearm—a disassembled Glock—had two serial numbers: a fully visible number on the slide and a partially visible number on the frame that had been scratched such that “several characters” were not legible or recognizable to the naked eye.

At sentencing, the Probation Office recommended, and the District Court applied, the four-level enhancement in U.S.S.G. § 2K2.1(b)(4)(B)(i) (2024 Guidelines), which applies if “any firearm had a serial number that was modified such that the original information is rendered illegible or unrecognizable to the unaided eye.” Craddock’s appeal squarely presented a textual question: does the existence of a separate legible serial number prevent the enhancement from applying?

II. Summary of the Opinion

The court affirmed. It reasoned that the text—particularly the breadth of “any firearm” and the indefinite article “a serial number”—requires only that at least one serial number on the firearm be modified to illegibility. Because the District Court found multiple characters on the frame serial number were not legible to the naked eye, the enhancement applied as written.

The court also rejected Craddock’s reliance on the Sentencing Commission’s 2024 amendment. The amendment, the court explained, was intended to resolve disagreements among circuits about what counts as “altered,” not to create an “escape hatch” where a firearm with multiple serial-number markings avoids the enhancement so long as one marking remains readable.

III. Analysis

A. Precedents Cited (and How They Shaped the Decision)

1. Standard of review and interpretive method

• United States v. Nasir, 17 F.4th 459, 468 (3d Cir. 2021) (en banc): Cited for plenary review of Guidelines interpretation. This anchored the Third Circuit’s posture: it reviewed the interpretive question “anew,” not deferentially.
• United States v. Caraballo, 88 F.4th 239, 243 (3d Cir. 2023): Reinforced that plenary review means no deference to the District Court’s interpretation, and supplied the textualist framework: presume “ordinary meaning” and consult dictionaries.
• Da Silva v. Att'y Gen., 948 F.3d 629, 635 (3d Cir. 2020): Quoted through Caraballo for the proposition that ordinary meaning governs and dictionaries are appropriate tools. The court then followed that instruction by defining “any,” “a,” “modify,” and “illegible.”

2. “Any” means expansive

• Ali v. Fed. Bureau of Prisons, 552 U.S. 214, 219 (2008): Used to underscore that “any” has an “expansive meaning.” The court imported this Supreme Court guidance to reject narrowing constructions that would effectively require all serial-number markings on a firearm to be illegible.
• United States v. Gonzales, 520 U.S. 1, 5 (1997): Quoted within Ali for the “one or some indiscriminately” gloss on “any,” reinforcing the enhancement’s breadth.

3. Indefinite article “a” / “an” commonly means “any” or “one”

• United States v. Warren, 820 F.3d 406, 408 (11th Cir. 2016): Cited for the interpretive point that “a” or “an,” when followed by a restrictive clause, often functions as “any” or “one.” This supported the Third Circuit’s conclusion that “a serial number” in § 2K2.1(b)(4)(B)(i) is satisfied by a single qualifying serial number.
• United States v. Alabama, 778 F.3d 926, 932 (11th Cir. 2015): Quoted within Warren for the same linguistic principle, lending additional judicial support to the ordinary-meaning reading.

4. Sister-circuit consensus on multiple serial numbers

The court noted its holding “accords with at least six of our sister circuits,” citing decisions that—under the pre-amendment enhancement—rejected the argument that all serial numbers must be affected:

• United States v. Serrano-Mercado, 784 F.3d 838, 850 (1st Cir. 2015)
• United States v. St. Hilaire, 960 F.3d 61, 65 (2d Cir. 2020)
• United States v. Jones, 927 F.3d 895, 897 (5th Cir. 2019)
• United States v. Sands, 948 F.3d 709, 713 (6th Cir. 2020)
• United States v. Thigpen, 848 F.3d 841, 845-46 (8th Cir. 2017)
• Warren, 820 F.3d at 408

Although these cases addressed earlier wording (“altered or obliterated serial number”), they mattered in two ways: (1) they demonstrated that courts have long read “a serial number” as satisfied by one affected serial number, and (2) they helped rebut Craddock’s suggestion that the 2024 amendment implicitly reversed that approach for firearms with multiple serial markings.

5. The 2024 amendment’s stated purpose

• Sentencing Guidelines for United States Courts, 89 Fed. Reg. 36853, 36858-59 (May 3, 2024): Cited as authoritative evidence of the Sentencing Commission’s intent. The Third Circuit used this to reject Craddock’s narrative that the amendment created a loophole for guns with multiple serial numbers; instead, the Commission aimed to “resolve[] the differences in how the circuits interpret[ed] the term ‘altered’.”

B. Legal Reasoning

1. The court’s “start and end” with the text

The opinion is deliberately textual. The court “start[s] and end[s]” with § 2K2.1(b)(4)(B)(i), treating the operative language as unambiguous when applied to a firearm with at least one illegible serial number.

2. The rule derived from “any” + “a serial number”

The court’s key interpretive move is syntactic: “any firearm” (broad category) paired with “a serial number” (indefinite article) indicates that the enhancement is triggered when at least one serial number on the firearm meets the “modified-to-illegible” condition. Nothing in the text requires that every serial number on the firearm be illegible, nor does it condition applicability on whether the firearm can still be traced using another marking.

3. “Modified” and “illegible” set a practical, perception-based threshold

By defining “modify” as making something “somewhat different” and “illegible” as not clear enough to read, the court framed the inquiry as: did someone make changes to the serial number such that the original characters cannot be read (or are difficult to make out) by the unaided eye? The District Court’s factual finding that “several characters” were not legible or recognizable satisfied that standard.

4. Rejection of Craddock’s “complete and accurate serial number” theory

Craddock argued that “any firearm” and “original information” should be read to mean the enhancement cannot apply if the firearm “as a whole” still bears a “complete and accurate serial number.” The court rejected this as an impermissible rewriting: “complete and accurate” does not appear in the guideline, and “original information” refers to the source/primary information of a serial number—not whether the gun remains traceable through another marking. Even under Craddock’s premise, the court emphasized, a firearm can simultaneously contain one legible serial number and another serial number rendered illegible—triggering the enhancement’s plain terms.

5. The 2024 amendment as clarification, not contraction

The opinion treats the 2024 amendment (changing “altered or obliterated” to “modified such that ... rendered illegible or unrecognizable to the unaided eye”) as clarifying the level of defacement required, not narrowing the enhancement in multi-serial-number scenarios. The court leveraged the Federal Register explanation to reinforce that the Commission sought uniformity on what “altered” meant and acted in light of tracing difficulties and market incentives associated with defaced serial numbers.

C. Impact

1. A clear, administrable Third Circuit rule

The decision establishes a straightforward rule for district courts within the Third Circuit: identify whether any one serial number on the firearm was modified so that the original characters are illegible or unrecognizable to the unaided eye. If yes, apply the four-level enhancement—regardless of whether another serial number remains readable.

2. Sentencing consequences in common fact patterns

Many modern firearms include serial markings on multiple components. After Craddock, defendants cannot avoid § 2K2.1(b)(4)(B)(i) by pointing to one intact marking when another has been defaced to illegibility. The likely practical effect is higher advisory ranges in cases involving partially defaced firearms, even where traceability might still be possible through another component.

3. Litigation will shift to the “unaided eye” and degree-of-legibility questions

Because the “multi-serial-number” argument is largely foreclosed in the Third Circuit, future disputes are more likely to focus on: (a) whether the serial number was “modified,” and (b) whether it is in fact illegible or unrecognizable “to the unaided eye” (e.g., partial readability, lighting, distance, normal eyesight). The opinion’s approach makes the district court’s factual findings about visual legibility especially important.

IV. Complex Concepts Simplified

• “Plenary review”: The court of appeals decides the legal interpretation question from scratch, without deferring to the district court’s reading.
• “Ordinary meaning” / dictionary use: When interpreting the Guidelines, the court gives words their everyday meaning and may consult reputable dictionaries to confirm that meaning.
• “Any firearm”: Broad phrasing that generally captures all firearms fitting the description; it does not imply a special “whole firearm” requirement that negates the rest of the sentence.
• Indefinite article “a”: Often means “one” or “any.” Here, “a serial number” means the enhancement is triggered if at least one serial number on the firearm was rendered illegible.
• “Modified such that ... rendered illegible or unrecognizable to the unaided eye”: A perception-based test. The question is whether the original serial characters cannot be read or identified by normal visual inspection without tools (not whether forensic techniques could recover the number).

V. Conclusion

United States v. Noah Craddock establishes (and, in the Third Circuit, decisively confirms) that § 2K2.1(b)(4)(B)(i) applies when a firearm contains at least one serial number modified to be illegible or unrecognizable to the unaided eye, even if another serial number on the same firearm remains legible. The opinion is a model of textual Guideline interpretation: it anchors the rule in the expansive force of “any” and the indefinite “a serial number,” rejects a-policy-driven narrowing that the text does not support, and reads the 2024 amendment as a clarification designed to standardize application rather than to create a loophole for firearms with multiple serial markings.