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19-640

United States v. St. Hilaire

United States Court of Appeals

for the Second Circuit

AUGUST TERM 2019

No. 19-640

UNITED STATES OF AMERICA,

Appellee,

v.

ROBERT ST. HILAIRE,

Defendant-Appellant.

ARGUED: FEBRUARY 7, 2020

DECIDED: MAY 21, 2020

Before: JACOBS, CALABRESI, CHIN, Circuit Judges.

Robert St. Hilaire appeals from the judgment of the United States District 

Court for the Eastern District of New York (Glasser, J.) following his guilty plea 

to possessing a firearm as a previously convicted felon, in violation of 

18 U.S.C. § 922(g). St. Hilaire challenges a four-level sentencing enhancement for 

possessing a firearm with “an altered or obliterated serial number,” imposed 

pursuant to U.S.S.G. § 2K2.1(b)(4)(B). We consider for the first time the meaning 

of that phrase and hold that a serial number is “altered” whenever any character 
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on any iteration of a gun’s serial number is illegible to the naked eye. Although 

the district court necessarily proceeded under precedents from other circuits that 

articulate a somewhat different standard, the court found as fact that at least one 

iteration of the serial number was illegible to the naked eye, a finding that is not 

clearly erroneous. Accordingly, we AFFIRM.

____________________

MATTHEW B. LARSEN, Federal Defenders of New 

York, New York, NY, for Defendant-Appellant Robert 

St. Hilaire.

JONATHAN E. ALGOR, Assistant United States 

Attorney (Samuel P. Nitze, Assistant United States 

Attorney, on the brief), for Richard P. Donoghue, 

United States Attorney for the Eastern District of New 

York, Brooklyn, NY, for Appellee United States of 

America.

Jacobs, Circuit Judge:

After Robert St. Hilaire pleaded guilty to being a felon in possession of a 

firearm, the United States District Court for the Eastern District of New York 

(Glasser, J.) applied a four-level sentencing enhancement pursuant to 

U.S.S.G. § 2K2.1(b)(4)(B) for possessing a firearm that “had an altered or 

obliterated serial number” (the “Enhancement”). Since this Court had not yet

considered what it means for a serial number on a gun to be altered or 
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obliterated, the district court relied on out-of-circuit case law. St. Hilaire argues 

that the Enhancement does not apply because, of the three serial numbers on his 

gun, one was clearly legible, thus dispelling ambiguity as to the iterations that 

were more scored and legible only in part. 

Consistent with our sister circuits, we hold that the Enhancement applies if 

a single iteration of a serial number has been altered or obliterated, 

notwithstanding whether another may be legible. Moreover, we hold that 

“altered” means illegible to the naked eye. Under the circumstances, it was not 

error for the district court to apply the Enhancement.

BACKGROUND

The few relevant facts are straightforward. St. Hilaire was arrested by the 

New York City Police Department on November 24, 2017, on suspicion of 

attempting to leave the scene of a car accident. A protective frisk turned up a 

loaded Taurus 9mm semiautomatic pistol. The police report prepared later that 

night described the gun as “SERIAL# TJN86665 WITH PARTIALLY DEFACED 

SERIAL#.” (App. at 12.) Using that number, the police made a Lost/Stolen 

Firearm Inquiry, which yielded “No Hits.” (App. at 22.)
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In general terms, a serial number is an identifier composed of a unique 

sequence of characters, mainly numbers or letters. Guns are usually 

manufactured with matching iterations of one serial number on different 

components, such as the frame and the slide. St. Hilaire’s gun bears a serial 

number in three places. One is slightly scratched but clearly legible; one is 

scratched but still shows most of the characters clearly; the third is so heavily 

scratched that some numbers are not obvious. The correspondences are 

sufficient that it would be uncanny for the numbers to baffle anyone who looks 

closely, makes deductions, and starts with the assumption that the serial 

numbers are likely the same. (App. at 24-27.)

Since St. Hilaire had been convicted of two state felonies, he was charged 

with one count of possessing a firearm as a previously convicted felon, in 

violation of 18 U.S.C. § 922(g); and he pleaded guilty. The PSR calculated his 

advisory range under the United States Sentencing Guidelines (the “Guidelines”) 

to be 84-105 months’ imprisonment based on a total offense level of 25 and a 

criminal history category IV. 

At the sentencing hearing (and in advance of it), St. Hilaire objected to the 

inclusion in that calculation of a four-level enhancement for possessing a firearm 
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that “had an altered or obliterated serial number.” See U.S.S.G. § 2K2.1(b)(4)(B). 

He argued that one iteration of the serial number on his gun was clear and that 

the characters on the others could be easily inferred. Since this Court had not 

construed the phrase “an altered or obliterated serial number,” the district court 

looked to out-of-circuit case law and applied the Enhancement, finding that “that 

serial number is not accessible to the eye, I couldn't tell what the numbers of the 

serial number on that gun were by looking at it.” (App. at 43.) St. Hilaire was 

sentenced below the Guidelines range to 60 months’ imprisonment (followed by 

three years’ supervised release). 

DISCUSSION

“We review the sentencing court's interpretation of the Sentencing 

Guidelines de novo, but review its related findings of fact only for clear error.” 

United States v. Potes-Castillo, 638 F.3d 106, 108 (2d Cir. 2011). This distinction 

matters because the district court both interpreted the Enhancement and made a 

factual finding about the serial numbers.

We conclude that a serial number can be altered or obliterated

notwithstanding that another iteration on the gun is legible (Point I). As to the 
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meaning of “altered or obliterated,” no question is raised in this case as to 

obliteration, which matters only for the light that it sheds on the meaning of 

alteration. As to alteration, we conclude that the test is whether the serial 

number can be read with the naked eye (Point II). 

 I

The Guidelines prescribe a four-level enhancement “[i]f any firearm . . . 

had an altered or obliterated serial number.” U.S.S.G. § 2K2.1(b)(4)(B). The 

Enhancement serves to “to discourag[e] the use of untraceable weaponry.” 

United States v. Serrano-Mercado, 784 F.3d 838, 850 (1st Cir. 2015) (alteration in 

original) (internal quotation marks omitted) (quoting United States v. Carter, 421

F.3d 909, 914 (9th Cir. 2005)). St. Hilaire emphasizes that the serial number on his 

gun was “clear in one place and merely less so in others,” and argues that just 

one legible iteration renders the Enhancement inapplicable. (Appellant’s Br. at 

5.) We disagree.

The Enhancement applies if a single iteration of a gun’s serial number has 

been altered or obliterated notwithstanding that another is perfectly legible. The 

wording references “an” altered or obliterated serial number; it “does not require 

that all of the gun's serial numbers be so affected.” Serrano-Mercado, 784 F.3d at 
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850. Since the component parts are interchangeable,1 matching serial numbers 

assure reliable identification of the firearm as a whole, and a single altered or 

obliterated serial number renders it more difficult to trace. 

Accordingly, the five Courts of Appeals that have considered the question 

hold that the Enhancement applies if any single iteration of a gun’s serial number

has been altered or obliterated. (The cases are in the margin.2) St. Hilaire argues 

that none of those cases say “a gun’s serial number is ‘altered’ if it appears 

clearly in one place and merely less so in others”; that the issue in all those cases 

was “the inability to tell if serial numbers on different parts of the gun matched”;

that the most legible iteration on his gun cures any ambiguity; and that his gun is 

thus easily traceable. (Reply Br. at 7.) However, the district judge here made a 

1 Firearms were among the first devices to be mass produced, after Samuel Colt 

pioneered the use of interchangeable parts. See Richard C. Rattenbury, Samuel 

Colt, Encyclopedia Britannica (Online ed. 2020).

2 See United States v. Sands, 948 F.3d 709, 713 (6th Cir. 2020) (“If a weapon has 

multiple serial numbers, only one of them needs to be altered or obliterated for 

the enhancement to apply.”); United States v. Jones, 927 F.3d 895, 897 (5th Cir. 

2019); (“We join the First, Eighth, and Eleventh Circuits in holding that the 

applicable guideline requires only that one serial number be altered or 

obliterated, even if others are clearly legible.”); United States v. Thigpen, 848 F.3d 

841, 845-46 (8th Cir. 2017) (same); United States v. Warren, 820 F.3d 406, 408 (11th 

Cir. 2016) (same); United States v. Serrano-Mercado, 784 F.3d 838, 850 (1st Cir. 

2015) (same).
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finding as to one of the serial numbers that he “couldn't tell what the numbers of 

the serial number on that gun were by looking at it.” (App. at 43.) It follows that 

the judge could not conclude that all the iterations matched.

Moreover, none of those cases hold (or suggest) that judges may not 

impose the Enhancement if a comparison of multiple serial numbers, some of 

them obscured or illegible, supports an inference that the numbers once 

matched. There are several good reasons why a court is not required to rely on 

inference to find that the numbers match. The purpose of the Enhancement is to 

“discourage the use of untraceable weaponry.” Carter, 421 F.3d at 915. That goal 

“is advanced not only by punishing those who possess untraceable firearms, but 

also by punishing those who possess firearms that are more difficult, though not 

impossible, to trace.” Id. at 914. “[T]he policy behind the enhancement--

deterrence and assisting law enforcement--is served even if law enforcement can 

ultimately identify the serial number and trace the firearm.” United States v.

Fuller-Ragland, 931 F.3d 456, 467 (6th Cir. 2019). Moreover, the scoring of serial 

numbers can obscure alteration made by the addition of strokes to change, e.g., a 

“J” to a “U” or a “1” to a “7”, or by the addition of a character, either in a number 

that otherwise appears legible or one that is partially obscured. In short, a gun
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with an indecipherable serial number on a single interchangeable part is just a

swap or two away from being untraceable. 

Accordingly, we hold that courts need to separately evaluate each iteration 

of a gun’s serial number, and that the Enhancement applies if just one has been 

altered or obliterated.

 II

The Guidelines do not define the term “altered or obliterated”; so we 

consider “the ordinary meaning of the words.” United States v. SKW Metals &

Alloys, Inc., 195 F.3d 83, 90 (2d Cir. 1999). We agree with our sister circuits that

“altered is less demanding than obliterated.” Sands, 948 F.3d at 714 (cleaned up) 

(quoting United States v. Harris, 720 F.3d 499, 503 (4th Cir. 2013)); see also

Carter, 421 F.3d at 912 (“Irrespective of how ‘obliterated’ is construed, ‘altered’ 

surely requires a lesser degree of defacement.”). Taking the dictionary 

definitions together in the context of a serial number, to obliterate is to efface 

entirely a character or a whole serial number, so that none of it is left. We 

therefore agree with the parties and the district court that there is no obliteration 

of the serial numbers on St. Hilaire’s gun.3 In each of the three serial numbers, 

3 The district court made no explicit finding as to obliteration, but its analysis 

focused on the meaning of “altered” and case law defining that term. Likewise, 
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including the two with severe scoring, one can easily count the number of 

characters, and make out some or most of them.4

More difficult is the question whether any of the serial numbers here were 

“altered.” Taking the dictionary definitions together in the context of serial 

numbers, “alteration” is to make different. Ways to alter a serial number are 

manifold. One kind of alteration, not at issue here, is the technique (used to 

falsify checks) of adding strokes that turn a “1” to a “4” or “7”; or a “3”, “6”, or 

“9” to an “8”. The tampering here was done by scratching, which leaves one

number legible, and two less so. 

We follow the Sixth Circuit, which defines “altered” to mean illegible. See

United States v. Sands, 948 F.3d 709, 715, 719 (6th Cir. 2020). In that case, the 

district court had applied the Enhancement notwithstanding its “factual finding 

the Government made no explicit concession, but implied as much by focusing 

on the definition of “altered” and the application of its proposed definition to the 

facts. (See Appellee’s Br. at 8 (“The district court correctly applied a four-level 

Guidelines enhancement pursuant to U.S.S.G. § 2K2.1(b)(4)(B) based on St. 

Hilaire’s possession of a firearm with an altered serial number.”).)

4 We need not decide whether a totally effaced but scientifically recoverable 

serial number qualifies as “obliterated.” See Carter, 421 F.3d at 912 (explaining 

that dictionary definitions of “obliterate” “reasonably could embrace a 

requirement that a serial number be obliterated not just beyond the unaided eye, 

but also beyond scientific recognition”).
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that the serial number was still readable,” reasoning that the defacement made it 

“much more difficult to read.” Id. at 718 (internal quotation marks omitted). 

The Sixth Circuit vacated the sentence, explaining that the district court’s 

analysis was “at odds with . . . the plain meaning of the word ‘altered’” insofar as 

it “applied the enhancement after finding that the serial number remained visible 

to the naked eye.” Id. at 718-19. Under this “naked eye test,” “a serial number 

that has been defaced but is still visible to the naked eye is not ‘altered or 

obliterated.’” Id. at 711, 717.

This “naked eye test” best comports with the ordinary meaning of 

“altered”; it is readily applied in the field and in the courtroom; it facilitates 

identification of a particular weapon; it makes more efficient the larger project of 

removing stolen guns from circulation; it operates against mutilation that 

impedes identification as well as mutilation that frustrates it; and it discourages 

the use of untraceable weapons without penalizing accidental damage or halfhearted efforts. “If a serial number is scratched, but still discernible to the reader 

without aid, . . . [t]he number remains the same, even to the casual observer.” Id.

at 715.
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Some circuits have ruled that a serial number can be “altered” 

notwithstanding that it remains legible. See United States v. Millender, 791 F. 

App’x 782, 783 (11th Cir. 2019) (affirming application of the Enhancement to a 

“severely scratched but legible” serial number and ruling that “the district court 

properly declined to adopt an interpretation of ‘altered’ that would require 

illegibility”); United States v. Perez, 585 F.3d 880, 884 (5th Cir. 2009) (affirming 

application of the Enhancement even though the “damage . . . did not render [the 

serial number] unreadable”). The Government urges us to follow these cases. 

(See Appellee’s Br. at 12 (“[A] serial number that has been made less legible has 

been ‘altered’ . . . even if it remains legible.”).) We decline the invitation. 

Other circuits have arguably implied that a legible serial number can still 

be “altered,” albeit in cases involving illegible serial numbers (and therefore 

cases that did not present the question). See United States v. Harris, 720 F.3d 

499, 503 (4th Cir. 2013) (“[A] serial number that is less legible or less

conspicuous, but not illegible, is also covered by [the Enhancement].”); United

States v. Carter, 421 F.3d 909, 916 (9th Cir. 2005) (“[A] firearm's serial number is 

‘altered or obliterated’ when it is materially changed in a way that makes 

accurate information less accessible.” (emphasis added)); see also United States v.
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Adams, 305 F.3d 30, 34 (1st Cir. 2002) (“[A]ny alteration that works against 

legibility is enough . . . .”). 

But setting aside how those three cases characterized their rulings, they

can be understood as consistent with the naked eye test, at least implicitly or in 

result.5 See Sands, 948 F.3d at 715 (explaining that the naked eye test

“is consistent with nearly every other federal appellate decision on the issue”). 

That is not surprising, given that readability is the intuitive test of alteration in 

this context. Serial numbers with some illegible characters are “more difficult” to 

trace (even if “not impossible”). Carter, 421 F.3d at 914. “Any person with basic 

vision and reading ability would be able to tell immediately whether a serial 

number is legible.” Sands, 948 F.3d at 717. It is useful and fair to “draw[] a clear 

line that should lessen confusion and inconsistency in the guideline’s application, 

5 The naked eye test would not affect the outcomes of these cases. The 

Enhancement would still apply since the serial numbers in each of them were 

illegible. In Harris, the district judge “was unable to read the correct serial 

number when ‘carefully’ examining it.” 720 F.3d at 504. In Carter, the defendant 

“concede[d] that the serial number on the firearm he possessed [was] ‘not 

decipherable by the naked eye.’” 421 F.3d at 910. And in Adams, one digit in the 

serial number was “damaged badly enough that it could be taken as a 3 or a 5.” 

305 F.3d at 35. 
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while at the same time leaving the district courts with appropriate discretion to 

conduct necessary factfinding at sentencing.” Id. 

We are unpersuaded by courts that reject legibility as a standard on the 

ground that it would render “obliterated” superfluous.6 Those observations do 

not take into account the many ways of tampering with a serial number, or the 

ways the terms can overlap: a serial number can be altered by obliteration of one 

or more characters; and the inability to read any appreciable part of a serial 

number can amount to obliteration in effect. Finally, we acknowledge that an 

artful change or addition to a serial number would of course read as legible to 

the naked eye, though it would render the original number illegible and thus 

altered. The facts of this case, in which the numbers were scored, do not present 

that issue. 

* * *

In this case, the district court applied the correct approach, assessing the 

iteration of the serial number that was most badly scored. Having done so, the 

6 See Millender, 791 F. App’x at 783 (“[T]he district court properly declined to 

adopt an interpretation of ‘altered’ that would require illegibility because that 

interpretation would render ‘obliterated’ superfluous.”); Harris, 720 F.3d at 503 

(“This interpretation that a serial number rendered less legible by gouges and 

scratches is ‘altered’ prevents the word ‘obliterated’ from becoming 

superfluous.”).
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court found as fact that it was illegible to the naked eye. That finding is not 

clearly erroneous. Imposition of the Enhancement under U.S.S.G. § 2K2.1(b)(4)(B) 

was not error. The judgment is AFFIRMED.