                FOR PUBLICATION

  UNITED STATES COURT OF APPEALS
       FOR THE NINTH CIRCUIT


UNITED STATES OF AMERICA,                 No. 11-10425
                Plaintiff-Appellee,
                                             D.C. No.
                 v.                       4:09-cr-02343-
                                           FRZ-GEE-1
YURIS BONILLA-GUIZAR,
             Defendant-Appellant.



UNITED STATES OF AMERICA,                 No. 11-10476
                Plaintiff-Appellee,
                                             D.C. No.
                 v.                       4:09-cr-02343-
                                           FRZ-GEE-2
CARLOS ARMANDO CALIXTRO-
BUSTAMANTE,
            Defendant-Appellant.            OPINION


      Appeal from the United States District Court
               for the District of Arizona
    Frank R. Zapata, Senior District Judge, Presiding

                Argued and Submitted
       May 13, 2013—San Francisco, California

                Filed September 9, 2013
2             UNITED STATES V. BONILLA-GUIZAR

     Before: M. Margaret McKeown and Paul J. Watford,
    Circuit Judges, and Algenon L. Marbley, District Judge.*

                    Opinion by Judge Marbley


                           SUMMARY**


                           Criminal Law

   The panel affirmed convictions for conspiracy to commit
hostage taking, hostage taking, and harboring an alien, but
vacated sentences and remanded for resentencing.

    The panel held that the district court did not abuse its
discretion in permitting a case agent to testify as an expert
witness. The panel explained that the agent’s testimony had
some probative value, and that because any error was
harmless, the panel did not need to decide whether the district
court erred in failing to distinguish clearly between the
defendant’s expert and percipient testimony and in failing to
offer a cautionary instruction. The panel noted the long-
standing precedent that bias is for the jury to consider in
determining the weight to accord the testimony.

    The panel vacated the district court’s application to
defendant Bonilla-Guizar of a two-level leadership


    *
     The Honorable Algenon L. Marbley, District Judge for the U.S.
District Court for the Southern District of Ohio, sitting by designation.
  **
     This summary constitutes no part of the opinion of the court. It has
been prepared by court staff for the convenience of the reader.
            UNITED STATES V. BONILLA-GUIZAR                  3

enhancement under U.S.S.G. § 3B1.1(c), where the record
was unclear whether the district court found Bonilla managed
another participant in the crime. The panel instructed that the
enhancement may be applied at resentencing on remand only
if the district court makes such a finding based on evidence
on the record.

    The panel held that the district court committed plain
error affecting substantial rights by applying to Bonilla and
defendant Calixtro-Bustamante an enhancement under
U.S.S.G. § 2A4.1(b)(3) for use of a dangerous weapon, where
the district court predicated the enhancement upon a legal
misunderstanding that brandishing the firearm was sufficient.


                         COUNSEL

Francisco Leon (argued), Law Office of Francisco Leon, P.C.,
Tucson, Arizona; Rosemary Márquez (argued), Márquez Law
Firm, P.L.L.C., Tucson, Arizona, for Defendants-Appellants.

Erica McCallum (argued), Assistant United States Attorney;
George Ferko, Special Assistant United States Attorney; John
S. Leonardo, United States Attorney; Christina M. Cabanillas,
Appellate Chief, United States Attorney’s Office, Tucson,
Arizona, for Plaintiff-Appellee.
4           UNITED STATES V. BONILLA-GUIZAR

                          OPINION

MARBLEY, District Judge:

    Defendants-Appellants, Yuris Bonilla-Guizar and Carlos
Armando Calixtro-Bustamante, appeal their respective
criminal convictions in a joint trial in the United States
District Court for the District of Arizona (“district court”) as
well as their subsequent sentences.             Bonilla-Guizar
(“Bonilla”) was convicted of conspiracy to commit hostage
taking and harboring an alien.            Calixtro-Bustamante
(“Calixtro”) was convicted of conspiracy to commit hostage
taking, hostage taking, and harboring an alien. Bonilla and
Calixtro both object to the following district court rulings: (1)
permitting a case agent to testify as an expert witness; and (2)
denying Defendants’ request for a limiting instruction to the
jury or other cautionary measure regarding the case agent’s
testimony. With respect to his sentence, Bonilla objects to
the district court’s application of a two-level enhancement,
under U.S.S.G. § 3B1.1(c), for his alleged leadership role in
the criminal activity. Finally, both Bonilla and Calixtro
object to the district court’s application of a two-level
sentencing enhancement, under U.S.S.G. § 2A4.1(b), for use
of a dangerous weapon.

    On appeal, we consider whether the district court erred in
allowing Case Agent Jeffrey Ellis (“Agent Ellis”) to testify as
an expert and, if it did not, whether the district court
nevertheless erred in failing to provide a cautionary
instruction to the jury regarding his testimony. Defendants
contend they were denied a fair trial because Agent Ellis
mixed factual testimony with expert testimony, and was
biased for the Government. On those grounds, Defendants
            UNITED STATES V. BONILLA-GUIZAR                   5

seek a reversal of their convictions and remand for a new
trial.

    We also consider alleged sentencing errors. Bonilla
argues that the district court erroneously applied the two-level
leadership enhancement to his sentence because the court had
not found that Bonilla supervised another participant in the
crime. In addition, Defendants both contend the district court
was wrong to apply a further two-level enhancement for use
of a dangerous weapon because the Government did not
prove that Appellants possessed actual firearms or “used” any
weapon beyond merely “brandishing” one. Hence, if we
affirm Defendants’ convictions, they alternatively seek to
vacate and to remand their sentences.

   For the reasons set forth herein, we AFFIRM Defendants’
convictions. We VACATE, however, the district court’s
application of a two-level leadership enhancement to Bonilla
and the application of a two-level enhancement to Bonilla and
Calixtro for use of a dangerous weapon.

                    I. BACKGROUND

    In mid-September, 2009, Julio Cesar Lopez-Trujillo
(“Lopez”) arranged to enter the United States illegally, from
Mexico, with assistance from alien smugglers. Lopez crossed
into the United States with five other aliens and two guides.
Upon crossing into Arizona, the guides instructed the aliens
to enter a truck waiting on the side of the road. Another
guide, called “El Flaco,” drove the truck while
communicating via handheld transceiver with someone
named “Yuri,” later identified as Bonilla. Bonilla told El
Flaco to drive to a particular restaurant and remain there.
Bonilla himself then arrived at the restaurant driving a small
6          UNITED STATES V. BONILLA-GUIZAR

car, and instructed El Flaco to follow him in the truck. The
group eventually arrived at a group of trailers near Tucson,
Arizona. Lopez and the other aliens were then moved into a
trailer.

    Two hours after Lopez arrived at the trailer, Bonilla
informed Lopez that he would have to pay $2,300 for the
assistance entering the U.S., rather than the $1,500 which
Lopez had been quoted in Mexico. Bonilla ordered Lopez to
call his wife to ask for the money. On September 22, 2009,
Lopez called his wife to tell her he would not be released
unless she sent his captors $2,300. Two days later, Calixtro
spoke to Lopez’s wife on the phone, and gave her instructions
for sending the money.

    Lopez testified that Bonilla and Calixtro were armed
during the time he was held hostage. In particular, Lopez
described one gun Defendants possessed which was black and
gray, approximately eight inches in length, and had a laser
sight and a magazine “loaded from underneath.” Lopez also
testified that both Defendants pointed that weapon at his
head.

    At approximately 7:40 p.m. on September 24, 2009,
federal agents freed Lopez and four other hostages. Federal
agents stated that, during the operation, they recovered two
firearms, including one very similar to the gun Lopez
described. The Government was unable to produce either of
those firearms at trial because, according to the Government,
they were accidentally destroyed while in the laboratory.

    At trial, the Government called Immigration and Customs
Enforcement (“ICE”) Special Agent Jeffrey Ellis (“Agent
Ellis”) to testify as an expert witness on alien smuggling and
            UNITED STATES V. BONILLA-GUIZAR                   7

alien smuggling operations. Agent Ellis had worked fifteen
years for ICE and its predecessor, the Immigration and
Naturalization Service.      For much of that time, he
investigated human smuggling. Agent Ellis was also the
original ICE case agent investigating Bonilla and Calixtro.
As part of the investigation, Agent Ellis prepared the search
warrant for the trailers where Lopez was found and worked
on the case for approximately four months. On cross-
examination, Agent Ellis admitted his bias for the
Government in this case. The district court, nevertheless,
qualified Agent Ellis as an expert witness and elected not to
give the jury any cautionary instruction with regard to his
testimony. Defendants’ trial counsel made evidentiary
objections to both rulings.

     The jury found Bonilla guilty of conspiracy to commit
hostage taking and harboring an alien for private financial
gain. At his sentencing, the district court applied a base
offense level enhancement of two for his role as “a manager
of some sort” in a criminal enterprise. The district court
applied a second two-level enhancement for Bonilla’s use of
a firearm in the commission of a crime. Those enhancements
raised Bonilla’s base offense level under the sentencing
guidelines from 32 to 36. The district court, relying on that
calculation, sentenced Bonilla to a 188-month term of
imprisonment.

    The jury found Calixtro guilty on three charges:
conspiracy to commit hostage taking; hostage taking; and
harboring an alien for private financial gain. At Calixtro’s
sentencing, the district court applied a base offense level
enhancement of two for Calixtro’s use of a firearm in the
commission of a crime. The enhancement raised the base
offense level from 32 to 34. The district court, relying on that
8            UNITED STATES V. BONILLA-GUIZAR

calculation, also sentenced Calixtro to a 188-month term of
imprisonment.

    Bonilla and Calixtro appeal both their convictions and the
sentencing enhancements.

                    II. JURISDICTION

    This Court has jurisdiction over final decisions of the
district court pursuant to 28 U.S.C. § 1291.

                      III. ANALYSIS

    A. District Court’s Admission of Agent Ellis’s Expert
                         Testimony

                   1. Standard of Review

   A district court’s decision to admit testimony of an expert
witness is reviewed for abuse of discretion. United States v.
Mejia-Luna, 562 F.3d 1215, 1218–19 (9th Cir. 2009).

                       2. Discussion

    Defendants argue that the district court abused its
discretion in permitting Agent Ellis, the original agent in the
investigation of Bonilla and Calixtro, to testify as an expert
witness. They contend that his expert testimony was of no
probative value, or of such limited probative value as to be
outweighed by the prejudicial effect. At the very least,
Defendants argue, the district court should have taken
“cautionary measures” to limit the potential prejudicial effect
of Agent Ellis’s testimony.
           UNITED STATES V. BONILLA-GUIZAR                  9

    Defendants first argue that Agent Ellis’s testimony lacked
probative value because the facts of this case were readily
comprehensible to jurors and the Government failed to
articulate how the testimony was relevant. Although
Defendants may not accept the Government’s theory of
relevancy, the Government did present one. The Government
suggested alien smuggling organizations are web-like, rather
than hierarchical, and involve a “loose confederation of co-
conspirators.” The facts of this case support that contention.
One person in Mexico solicited Lopez. A different set of
guides led him through the desert. Yet another man drove the
truck to the stash house. Finally, Defendants held Lopez at
the stash house and were in contact with a “boss.”

    While the scenario of a hostage taking may be familiar to
a layperson, the modus operandi of alien smugglers is less
familiar. As the district court found:

       Mr. Ellis is not an expert that is speaking on
       scientific matters that might require having
       read treatises or made studies and so forth.
       He’s testifying about the overall structure and
       operation of an alien smuggling organization
       . . . It’s information that is being imparted to
       a jury who presumably knows nothing about
       alien smuggling and alien smuggling
       organizations.

The district court, following Ninth Circuit precedent, agreed
with the Government that the structure of an alien smuggling
organization was relevant to the charge of conspiracy.
Indeed, this Court has repeatedly upheld the admission of
expert testimony “regarding the structure and methods of
alien smuggling operations.” Mejia-Luna, 562 F.3d at
10          UNITED STATES V. BONILLA-GUIZAR

1218–19. Thus, Agent Ellis’s testimony as an expert witness
had some probative value.

    Defendants next argue that, even if Agent Ellis’s
testimony had some probative value, such value was
outweighed by its prejudicial effect. In particular, Defendants
allege that Agent Ellis’s testimony was unfairly prejudicial
because “qualifying the case agent as the expert witness . . .
unduly bolster[ed] the credibility of the government’s case.”

    This court has previously considered the challenges that
are created when a case agent testifies as both an expert and
percipient witness. See United States v. Freeman, 498 F.3d
893, 902–04 (9th Cir. 2007); see also United States v.
Dukagjini, 326 F.3d 45 (2d Cir. 2003). In Freeman, we held
that a case agent is not categorically barred from testifying as
both an expert and percipient witness, “provided that the
district court engages in vigilant gatekeeping” and that
“jurors are aware of the witness’s dual roles” and the bounds
of each type of testimony. 498 F.3d at 904. We considered
a similar situation in United States v. Anchrum, 590 F.3d 795,
803–04 (9th Cir. 2009), and affirmed a guilty verdict where
a case agent testified in both roles because “the district court
divided [the case agent’s] testimony into two separate
phases,” which “avoided blurring the distinction between [the
case agent’s] distinct role as a lay witness and his role as an
expert witness.”

    Defendants concede that the direct examination solely
addressed Agent Ellis’s expert opinion. Agent Ellis’s role as
a case agent was first raised by Defendants’ counsel on cross-
examination to challenge Agent Ellis’s impartiality. On
cross-examination and redirect-examination, Agent Ellis
answered, as a percipient witness, several questions about the
            UNITED STATES V. BONILLA-GUIZAR                 11

investigatory process, primarily focused on the description in
the warrant application of the location to be searched.

    Agent Ellis’s expert testimony placed Defendants in a
difficult position. Defendants could reasonably fear that
Agent Ellis’s involvement in the investigation could bias his
expert testimony and that he could “stray from applying
reliable methodology and convey to the jury the witness’s
‘sweeping conclusions’ about appellants’ activities, deviating
from the strictures of Rules 403 and 702.’” Freeman,
498 F.3d at 903 (citations omitted). At the same time,
exposing an expert witness’s role as case agent generally
creates concerns that his expert status will reinforce the
credibility of his percipient testimony.

    The defense requested a cautionary instruction, but the
court declined to give one. Defendants argue that the district
court failed to take appropriate measures to “guard against the
risk of confusion inherent when a law enforcement agent
testifies as both a fact witness and as an expert witness.” We
agree that extra precautions are necessary when a case agent
testifies as an expert and a fact witness. See Freeman,
498 F.3d at 904. The government suggests that Agent Ellis’s
lay testimony was so minimal that he should not be
considered a fact witness. Nonetheless, Agent Ellis did
testify about the facts of this specific case based on his own
experience as a case agent, thereby exceeding the bounds of
his expert role. We need not decide whether the district court
erred in failing to distinguish clearly between Ellis’s expert
and percipient testimony and in failing to offer a cautionary
instruction to the jury, however, because any potential error
in this case was harmless.
12          UNITED STATES V. BONILLA-GUIZAR

     For the purposes of harmless error analysis, we proceed
under the presumption that a trial error occurred. A
non-constitutional trial error requires reversal unless “it is
more probable than not that the error did not materially affect
the verdict.” See United States v. Seschillie, 310 F.3d 1208,
1214 (9th Cir. 2002). Agent Ellis’s lay testimony was elicited
primarily by defense counsel. His testimony established that
the government had no listening devices or cameras in the
trailer prior to the arrest and that Agent Ellis therefore relied
on what he was told by Lopez and his wife in preparing the
warrant application. Defense counsel also elicited testimony
regarding the size and layout of the property described in the
warrant and the accuracy of the location data provided by the
cellular phone carrier. On redirect examination, the
government briefly reviewed Agent Ellis’s request in the
affidavit to search all of the trailers on the property because
of the range of accuracy of the locational data.

    None of this fact testimony from Agent Ellis established
any elements of the crime or was material to the conviction.
Nor could the jury have been swayed to grant more weight to
Ellis’s expert testimony here by the few facts he recited about
the search warrant application. In light of the overwhelming
evidence of guilt, we can say with at least a “fair assurance”
that any error did not affect the verdict and was therefore
harmless. United States v. Morales, 108 F.3d 1031, 1040 (9th
Cir. 1997) (en banc).

    Defendants also argue that the district court should not
have admitted Agent Ellis’s testimony on account of bias.
But it is axiomatic that a witness’s “possible bias” goes “to
the weight of her testimony, not its admissibility.” United
States v. Moore, 580 F.2d 360, 364 (9th Cir. 1978). Indeed,
the Supreme Court has observed:
            UNITED STATES V. BONILLA-GUIZAR                  13

       A more particular attack on the witness’
       credibility is effected by means of cross-
       examination directed toward revealing
       possible biases, prejudices, or ulterior motives
       of the witness as they may relate directly to
       issues or personalities in the case at hand.
       The partiality of a witness is subject to
       exploration at trial, and is ‘always relevant as
       discrediting the witness and affecting the
       weight of his testimony.’

Davis v. Alaska, 415 U.S. 308, 316 (1974) (internal citations
omitted). Here, Defendants’ trial counsel attempted to
impeach the credibility of Agent Ellis by exposing his bias on
cross-examination. The jury was able to factor the bias into
its consideration of Agent Ellis’s credibility.

     Any time a party attempts to impeach a witness’s
credibility, there is an inherent risk that a jury will not find
the credibility of the witness impaired, or even that a failed
impeachment may bolster a witness’s credibility. The fact
that Agent Ellis’s potential bias happened to result from his
employment by the Government is also not grounds for
categorically barring his testimony; it is simply another factor
the jury may consider in weighing Agent Ellis’s credibility.
Hingson v. Pacific Southwest Airlines, 743 F.2d 1408,
1412–13 (9th Cir. 1984). Nor does the analysis change
because Agent Ellis admitted to having some bias for the
Government. Although the admission may have had the
effect of enhancing his credibility, that is a risk Defendants’
trial counsel took when attempting to impeach Agent Ellis.
Agent Ellis also testified he had done his best to separate his
role in the case from the opinions he rendered as an expert.
Given the long-standing precedent that bias is for the jury to
14          UNITED STATES V. BONILLA-GUIZAR

consider in determining the weight to accord testimony, we
hold the district court did not abuse its discretion in admitting
Agent Ellis’s testimony.

     Defendants’ convictions are, therefore, AFFIRMED.

      B. Defendant Bonilla’s § 3B1.1 Enhancement

                   1. Standard of Review

    The factual findings made by the district court in the
sentencing phase are reviewed for clear error. United States
v. Kimbrew, 406 F.3d 1149, 1151 (9th Cir. 2005). The
district court’s application of the Sentencing Guidelines to the
facts of the case is reviewed for abuse of discretion. Id.

                        2. Discussion

    Section 3B1.1(c) of the Sentencing Guidelines provides
that:

        If the defendant was an organizer, leader,
        manager, or supervisor in any criminal
        activity other than described in (a) or (b),
        increase by 2 levels.

The commentary goes on to note that:

        To qualify for an adjustment under this
        section, the defendant must have been the
        organizer, leader, manager or supervisor of
        one or more other participants. An upward
        departure may be warranted, however, in the
        case of a defendant who did not organize,
           UNITED STATES V. BONILLA-GUIZAR                15

       lead, manage or supervise another participant,
       but who nevertheless exercised management
       responsibility over the property, assets, or
       activities of a criminal organization.

U.S.S.G. § 3B1.1, cmt. n. 2. In this circuit, however, “some
degree of control or organizational authority over others is
required in order for section 3B1.1 to apply.” United States
v. Mares-Molina, 913 F.2d 770, 773 (9th Cir. 1990)
(emphasis added). “Participant,” in § 3B1.1, is defined as “a
person who is criminally responsible for the commission of
the offense, but need not have been convicted.” U.S.S.G.
§ 3B1.1, at cmt. n. 1.

     The district court found Bonilla “was basically a house
sitter, stash house sitter, that takes control in this case
apparently by use of a firearm of people who are there . . .
And to some degree I think you can probably find that he was
a manager of some sort of the people in the house.” The
district court then added that it found “without much effort
[Bonilla] was in fact some sort of – certainly he was
managing the house there where he was and also supervising
whatever went on in that house.”

    On appeal, Bonilla argues that the district court
misinterpreted the definition of “participant” to encompass a
“hostage or victim of the crime.” From the record, it is
unclear whether the district court made such a
misinterpretation. The vague findings that Bonilla “was a
manager of some sort of the people in the house” and
“whatever went on in that house” could equally have referred
to other participants or the hostages themselves. Although we
review the district court’s decision in this matter for clear
error, from the record, we do not know whether the district
16          UNITED STATES V. BONILLA-GUIZAR

court found Bonilla managed another participant in the crime.
If the district court found Bonilla did not manage or supervise
another participant in the crime, the application of the
enhancement would be clear error, in light of Mares-Molina.
We cannot affirm a decision that is ambiguous and, thus,
unclear. It is, therefore, necessary to vacate Bonilla’s
sentence and remand him to the district court for
resentencing. Upon resentencing, the district court may apply
the § 3B1.1 management enhancement only if it finds, based
on evidence in the record, that Bonilla managed at least one
other participant in the crime. For these reasons, the sentence
of Bonilla is VACATED and he is remanded to the district
court for resentencing.

     C. Defendants’ U.S.S.G. § 2A4.1(b)(3) Firearm
                    Enhancements

                   1. Standard of Review

    Where a defendant has failed to raise an objection to a
sentencing error in the district court, the decision is reviewed
for plain error. United States v. Ameline, 409 F.3d 1073,
1078 (9th Cir. 2005). Defendant Calixtro did not object to
the dangerous weapon enhancement. Defendant Bonilla
objected on due process grounds, which are not raised on this
appeal.

    Plain error is: “(1) error, (2) that is plain, and (3) that
affects substantial rights.” United States v. Cotton, 535 U.S.
625, 631 (2002). Once those three conditions are satisfied,
“an appellate court may exercise its discretion to notice a
forfeited error that (4) ‘seriously affects the fairness,
integrity, or public reputation of judicial proceedings.’”
Ameline, 409 F.3d at 1078 (citation omitted). A defendant
           UNITED STATES V. BONILLA-GUIZAR                 17

bears the burden to show her substantial rights were affected
and, to do so, “must establish ‘that the probability of a
different result is sufficient to undermine confidence in the
outcome of the proceeding.’” Id. (citation omitted).

                       2. Discussion

    Under U.S.S.G. § 2A4.1(b)(3), a two-level sentence
enhancement applies to an offense of kidnapping, abduction,
or unlawful restraint “[i]f a dangerous weapon was used.”
The commentary clarifies that “‘[a] dangerous weapon was
used’ means that a firearm was discharged, or a ‘firearm’ or
‘dangerous weapon’ was ‘otherwise used’ [] as defined in the
commentary to § 1B1.1.” U.S.S.G. § 2A4.1, cmt. n. 2.
Section 1B1.1 goes on to define “dangerous weapon” as “an
instrument capable of inflicting death or serious bodily
injury” or “an object that is not an instrument capable of
inflicting death or serious bodily injury but (I) closely
resembles such an instrument; or (II) the defendant used the
object in a manner that created the impression that the object
was such an instrument.” U.S.S.G. § 1B1.1, cmt. n. 1(D).

    “Otherwise used,” when referring to a dangerous weapon,
“means that the conduct did not amount to the discharge of a
firearm but was more than brandishing, displaying, or
possessing a firearm or other dangerous weapon.” Id. at cmt.
n. 1(I).

    Although § 1B1.1 explicitly states that merely
“brandishing, displaying, or possessing” a dangerous weapon
alone does not qualify as “otherwise us[ing],” the district
court found:
18           UNITED STATES V. BONILLA-GUIZAR

        [W]hether or not it was actually pointed
        directly at the victim, under the guidelines
        that does not appear to be necessary; only that
        the weapon was possessed and that the
        weapon was displayed.

That finding contradicts the plain language of § 1B1.1 and,
thus, is “(1) error, (2) that is plain” in the plain error analysis.
The Government concedes that the district court’s finding
satisfies the first two prongs of the plain error test.
According to the Government, however, that plain error
neither affects the Defendants’ substantial rights, nor the
public reputation of the judicial system.

    We reject the Government’s position that Defendants’
substantial rights were not affected by the district court’s
error. The Supreme Court has held that “improperly
calculating the Guidelines range” is a “significant procedural
error.” Gall v. United States, 552 U.S. 38, 51 (2007). We
subsequently held that “[a] mistake in calculating the
recommended Guidelines sentencing range is a significant
procedural error that requires us to remand for resentencing.”
United States v. Munoz-Camarena, 631 F.3d 1028, 1030 (9th
Cir. 2011) (emphasis added). If the district court mistakenly
based its application of the firearm enhancement on
brandishing alone, then it improperly calculated the
Guidelines sentencing range.

    The Government correctly contends that there was
testimony from Lopez that both Bonilla and Calixtro pointed
a gun at his head – conduct that goes beyond brandishing. At
sentencing, however, the district court found that “[t]he
defense, by the destruction of that firearm, was to some
degree denied the opportunity to cross-examine” Lopez as to
            UNITED STATES V. BONILLA-GUIZAR                  19

whether Bonilla and Calixtro pointed a gun at him, and how
he knew that. The district court went on to say that:

       if the standard that we’re looking at is it was
       more than brandishing, displaying or
       possessing a firearm, then we’re probably not
       going to be able to get there because the
       firearm was destroyed. The defendant’s
       ability to cross-examine on that issue was
       curtailed to a large degree.

In other words, contrary to the Government’s contention, the
district court explicitly declined to find Bonilla and Calixtro
had pointed a firearm at Lopez, or used it in any way except
by brandishing. The resulting enhancement was predicated
upon the legal misunderstanding that brandishing a firearm
alone supported an enhancement under § 2A4.1. It does not.
Had the district court not applied the enhancement it would
have calculated lower base offense levels and, though the
Guidelines are advisory, there is a high probability that lesser
sentences would have been imposed.

    As a result of the district court’s sentencing errors,
Bonilla’s base offense level was raised from 32 (sentencing
range of 121–151 months) to 36 (sentencing range of
188–235 months). We have held that when a sentencing
judge incorrectly calculates the Guidelines range, potentially
resulting in the imposition of a greater sentence, the error
affects the defendant’s substantial rights and “the fairness of
the judicial proceedings.” United States v. Castillo-Marin,
684 F.3d 914, 927 (9th Cir. 2012). As this is precisely what
happened in this case, the third and fourth prongs of the plain-
error test are satisfied.
20          UNITED STATES V. BONILLA-GUIZAR

    The situation of Calixtro is somewhat different. The
sentencing error raised his base offense level from 32
(sentencing range of 168–210 months) to 34 (sentencing
range of 210–262 months). The district court applied a
downward variance in sentencing Calixtro to 188 months.
Had the district court properly calculated Calixtro’s
sentencing range, it may still have applied the downward
variance, resulting in a sentence of less than 188 months. The
fact that Calixtro’s actual sentence chanced to fall within the
proper sentencing range does not alter the fact that the district
court plainly erred when calculating the range of his sentence,
thus affecting his substantial rights.

    We, therefore, hold the district court plainly erred in
applying the § 2A4.1(b)(3) enhancement to Defendants’
sentences. Upon resentencing Defendants, the district court
may find convincing the evidence that Defendants pointed a
gun at their victim, but we decline the Government’s request
to do so on appeal when the district judge who heard all the
evidence explicitly did not. For these reasons, the sentences
of Bonilla and Calixtro are VACATED and remanded to the
district court for resentencing.

                    IV. CONCLUSION

    For the foregoing reasons, we AFFIRM the district
court’s admission of Agent Ellis’s expert testimony and
Defendants’ convictions. As a result of sentencing errors, we
VACATE Defendants’ sentences and REMAND them to the
district court for resentencing consistent with this Opinion.

  AFFIRMED in part, VACATED in part and
REMANDED.
