          United States Court of Appeals
                 For the First Circuit

No. 15-1812

                UNITED STATES OF AMERICA,

                        Appellee,

                           v.

                     JAMES DUNSTON,

                  Defendant, Appellant.


No. 15-1999

                UNITED STATES OF AMERICA,

                        Appellee,

                           v.

                    SERGIO HERNANDEZ,

                  Defendant, Appellant.

                  ____________________

No. 15-2000

                UNITED STATES OF AMERICA,

                        Appellee,

                           v.

                   ANTHONY WOOLDRIDGE,

                  Defendant, Appellant.

                  _____________________
          APPEALS FROM THE UNITED STATES DISTRICT COURT
                FOR THE DISTRICT OF MASSACHUSETTS

         [Hon. Timothy S. Hillman, U.S. District Judge]


                             Before

                      Barron, Circuit Judge,
                   Souter, Associate Justice,
                    and Selya, Circuit Judge.



     Peter J. Cyr, with whom Law Offices of Peter J. Cyr were on
brief, for appellant Wooldridge.
     Michael D. Day, with whom The Day Law Firm, LLC was on brief,
for appellant Hernandez.
     Xiomara M. Hernández on brief for appellant Dunston.
     Mark T. Quinlivan, Assistant United States Attorney, with
whom Carmen M. Ortiz, United States Attorney, was on brief, for
appellee.


                         March 15, 2017





  Hon. David H. Souter, Associate Justice (Ret.) of the Supreme
Court of the United States, sitting by designation.
             SELYA, Circuit Judge.    In cases in which defendants are

accused of trafficking in narcotics, drug quantity is often both

an element of the offense and a critical integer in the sentencing

calculus.    These appeals illustrate that duality and, at the same

time, serve to explicate the shifting standards of proof that

pertain.      Because   the   court   below   applied   these   standards

appropriately, we affirm both of the challenged convictions and

two of the three challenged sentences.        With respect to the third

sentence, though, the government concedes that the district court

relied on too weak a foundation in classifying the defendant as a

career offender and we are not persuaded by the government's

attempt to brand the error harmless.          We therefore remand that

sentence for further proceedings consistent with this opinion.

I.   BACKGROUND

             We start with an overview of the case, drawing relevant

facts from the trial transcripts, line sheets of recorded telephone

calls introduced into evidence, and (where appropriate) undisputed

portions of the defendants' presentence investigation reports.

             This case has its roots in an investigation into drug

dealing in and around Worcester, Massachusetts, commenced by the

Drug Enforcement Administration (DEA) and local police officers.

The probe initially focused on defendants James Dunston and Sergio

Hernandez.    Its scope later expanded to include defendant Anthony

Wooldridge.


                                  - 3 -
             The   investigation     was     launched    with      a    number     of

controlled buys: between January and June — all dates are in 2012

unless otherwise indicated — an undercover DEA agent bought nearly

forty-four grams of crack cocaine from Dunston and Hernandez in

sixteen separate transactions.           Intelligence gained during these

sorties furnished the basis for properly authorized wiretaps on

both   Hernandez's    telephone    and     the    telephone   of       yet    another

coconspirator (Richard Cruz).            Between June and September, the

agents intercepted close to 30,000 calls and text messages.                       The

wiretapped    intercepts   indicated       that    Dunston,     Hernandez,        and

Wooldridge were regularly dealing crack cocaine in Worcester and

its environs.

             The wiretaps revealed, inter alia, that the defendants

acquired powder cocaine on no fewer than seven occasions in the

summer months and attempted at least one further acquisition.

Shortly   after    receiving   the    powder,      the   defendants          promptly

converted it to crack.     They frequently discussed crack conversion

techniques, described the results of particular conversions, and

boasted about their ability to convert powder to crack without

losing any appreciable drug weight.

             It is said that all good things come to an end and, in

July, Wooldridge was arrested during a traffic stop after police

officers conducted a pat-frisk and found ninety-three grams of

crack cocaine on his person.         Dunston and Hernandez were arrested


                                     - 4 -
in September.     All three were charged with conspiring to possess

with intent to distribute both crack cocaine and powder cocaine.

See 21 U.S.C. §§ 841(a)(1), 846.              Additionally, Wooldridge was

charged with possession of crack cocaine with intent to distribute,

see id. § 841(a)(1), and Hernandez was charged with being a felon

in   possession   of    a   firearm    and     ammunition,      see   18   U.S.C.

§ 922(g)(1).

           After some preliminary skirmishing, all three defendants

waived indictment and pleaded guilty to superseding informations

charging them with, as relevant here, conspiring to possess with

intent to distribute crack cocaine.                The informations specified

that the charged conspiracy "involved 280 grams or more of a

mixture and substance containing a detectable amount of cocaine

base" — a quantity sufficient to trigger a ten-year mandatory

minimum sentence.      See 21 U.S.C. § 841(b)(1)(A)(iii).

           Each    defendant      pleaded      guilty      to   the   underlying

conspiracy offense, reserving, however, the right to contest at a

bench   trial   whether     the   amount      of   crack   cocaine    reasonably

foreseeable or attributable to him was 280 grams or more (thus

exposing him to the mandatory minimum sentence).                  The district

court thereafter held an eight-day bench trial, at which it heard,

inter alia, recordings of intercepted calls as well as testimony

from a DEA agent (Timothy Boyle), who interpreted the slang and

jargon that permeated in the recordings.             At the conclusion of all


                                      - 5 -
the evidence, the court found "beyond a reasonable doubt that over

280   grams    of   cocaine    base   [wa]s   attributable   and   reasonably

foreseeable to all defendants."

              The district court ordered the probation department to

prepare individual presentence investigation reports.                 At the

disposition hearings, the court adopted the reports without change

and classified all three defendants as career offenders under the

sentencing guidelines.          It found Wooldridge responsible for at

least 840 grams of crack cocaine and sentenced him to a 132-month

term of immurement.          With respect to Dunston and Hernandez, the

court found each of them responsible for at least 2.8 kilograms

(2,800 grams) of crack cocaine; sentenced Dunston to 144 months'

imprisonment; and sentenced Hernandez to 162 months' imprisonment.

These timely appeals followed.

II.   ANALYSIS

              The defendants' appeals have been consolidated, and we

turn first to the claims of error that implicate their convictions.

From that point, we proceed to their claims of sentencing error.

                        A.    Lay Opinion Testimony.

              Dunston contends that the district court should not have

allowed Agent Boyle to testify about the meaning of slang terms

and jargon used in the course of the wiretapped conversations.            He

submits that although Boyle may have been qualified to give some

lay opinion testimony, the government failed to erect an adequate


                                      - 6 -
foundation for his interpretations of particular slang terms.          To

illustrate his point, Dunston notes that Boyle was allowed to

testify that the word "tweezy" referred to crack cocaine and that

the phrase "step up a yard" referred to turning powder into crack.

In   Dunston's   view,   Boyle's   familiarity   with    the   defendants'

conversations did not qualify him to give an informed opinion about

the meaning of these and other specific phrases used within those

conversations.    We do not agree.

             All three defendants raised this issue below, but only

Dunston pursues it on appeal.         Objections to the admission of

evidence are reviewed for abuse of discretion.          See United States

v. Valdivia, 680 F.3d 33, 50 (1st Cir. 2012).           The parties agree

that Agent Boyle's testimony should be considered lay opinion

testimony.    Hence, Federal Rule of Evidence 701 controls.        See id.

Rule 701 permits the admission of lay opinion testimony "rationally

based on the witness's perception" that would help the factfinder

"determin[e] a fact in issue."

             Application of Rule 701 in the drug-trafficking context

is not novel: "we have long held that government witnesses with

experience in drug investigations may explain the drug trade and

translate coded language" for factfinders through lay opinion

testimony.     United States v. Rosado-Pérez, 605 F.3d 48, 56 (1st

Cir. 2010); accord United States v. Hoffman, 832 F.2d 1299, 1310

(1st Cir. 1987) (holding that "interpretation of codes and jargon


                                   - 7 -
used in the drug trade can be supplied through one experienced in

the field").   Such testimony is especially useful where, as here,

it can afford the factfinder the benefit of specialized knowledge.

See United States v. Albertelli, 687 F.3d 439, 446 (1st Cir. 2012).

            Of course, such interpretive testimony must be anchored

in the witness's personal experience in the field, see Hoffman,

832 F.2d at 1310, and his experience-based understanding of the

meaning of the terms used, United States v. Prange, 771 F.3d 17,

28 & n.3 (1st Cir. 2014).     Put another way, "an interpretation of

a phrase or reference ought to be explicable" — a standard that

typically requires the witness to point to similar statements

surrounding similar events.     Albertelli, 687 F.3d at 450.

            In the case at hand, the government erected a sturdy

foundation for Boyle's testimony.      The record reflects that Boyle

had a twenty-four-year career in law enforcement, with significant

experience in undercover drug investigations.             He had received

specialized training in narcotics enforcement, had participated in

over fifteen wiretap investigations, and had supervised more than

twenty other such investigations.         As part of his duties, he had

reviewed    audio   and   videotape   from   undercover    crack   cocaine

purchases "hundreds" of times and had taken part at least once in

an undercover operation in which he observed powder being converted

to crack.




                                  - 8 -
             In this particular probe, Boyle reviewed nearly all of

the 30,000 calls and texts collected during the wiretaps.               He not

only drew on his extensive experience to inform his understanding

of specific slang terms but also took into account the context in

which those terms were used.             Boyle explained that he often

listened to "several calls leading up to" the use of a given bit

of slang as well as "conversations that would take place after

that" to ensure his understanding.

             Confronted with objections, the district court prudently

allowed defense counsel to conduct a voir dire and question Boyle

about his credentials, his experience, and his knowledge.                 This

additional safeguard, coupled with Boyle's cross-examination by

all three defense attorneys, mitigated any risk of unfair prejudice

from his testimony.       See United States v. Henry, ___ F.3d ___, ___

(1st Cir. 2017) [No. 15-2487, slip op. at 21]; Albertelli, 687

F.3d at 447.

             Where malefactors try to mask their criminal activities

by using codes, a law enforcement officer who is equipped by

knowledge, experience, and training to break those codes can help

to inform the factfinder's understanding.               So it is here: the

government     provided   the   district    court   with     ample   reason   to

conclude that Boyle was knowledgeable about the idiom of the drug

trade   and,    in   particular,   the     vernacular   of    this   group    of

miscreants.     On this record, we hold, without serious question,


                                   - 9 -
that the admission of Boyle's lay opinion testimony was comfortably

within the ambit of the district court's discretion.

                   B.   Sufficiency of the Evidence.

             The next leg of our journey takes us to Dunston's and

Wooldridge's claims that the district court lacked sufficient

evidence to find them guilty of the charged offense.    These claims

share a common focus: they are aimed at the district court's

finding, at trial, that at least 280 grams of crack cocaine was

"attributable and reasonably foreseeable" by the defendant making

the claim.    Such a defendant-specific finding is an element of the

offense of conviction: it means that a defendant cannot, simply by

reason of his membership in a conspiracy that traffics in large

amounts of drugs, automatically be "saddled with the full weight

of the conspiracy's wrongdoing."      United States v. Sepulveda, 15

F.3d 1161, 1197 (1st Cir. 1993).     He can only be held responsible

for drugs that he "personally handled or anticipated handling," as

well as "drugs involved in additional acts that were reasonably

foreseeable by him and were committed in furtherance of the

conspiracy."     Id.

             Here, the district court held a bench trial on the drug-

weight issue — a trial that was necessary because any fact that

increases the mandatory minimum sentence for an offense must,

absent a plea or a stipulation, be submitted to a factfinder to be

determined beyond a reasonable doubt.        See Alleyne v. United


                                 - 10 -
States, 133 S. Ct. 2151, 2155 (2013) (citing Apprendi v. New

Jersey, 530 U.S. 466, 483 n.10, 490 (2000)); United States v.

Pizarro, 772 F.3d 284, 292-93 (1st Cir. 2014).      At the end of the

trial, the court found that each of the defendants was responsible

for at least 280 grams of crack cocaine.

          Hernandez   does     not      appeal   the    drug-quantity

determination as it relates to him.       Dunston and Wooldridge do

appeal and, as to each of them, we must "examin[e] the facts and

inferences in the light most favorable to the verdict."        United

States v. O'Donnell, 840 F.3d 15, 18 (1st Cir. 2016) (citation

omitted); cf. United States v. Colon-Solis, 354 F.3d 101, 103 (1st

Cir. 2004) (requiring "defendant-specific determination of drug

quantity" for this purpose).    The ultimate question is whether,

after viewing the evidence in the light most hospitable to the

government, a rational trier of fact could have found the drug-

weight elements beyond a reasonable doubt.       See United States v.

Grace, 367 F.3d 29, 34 (1st Cir. 2004).          We must answer this

question separately as to each of the two appealing defendants,

see Colon-Solis, 354 F.3d at 103, exercising de novo review.      See

O'Donnell, 840 F.3d at 18.

          With this preface, we turn to the substance of the

sufficiency claims.    We begin with Dunston and then move to

Wooldridge.




                               - 11 -
           1.   Dunston.   Dunston contends that the court's finding

that he was responsible for at least 280 grams of crack cocaine

was plucked out of thin air.        Pointing out that the authorities

never seized any of the drugs to which he alluded in the wiretapped

conversations, he insists that it remains unclear how much powder

was converted to crack.

           Dunston is whistling past the graveyard.       The government

presented evidence linking Dunston to at least eight separate

transactions.    We need examine only two of these occurrences to

defuse Dunston's attack.

           On June 26, the government intercepted a telephone call

in which Dunston and Hernandez discussed their plans to cook 200

grams of powder cocaine recently purchased from Wooldridge.          The

two men split the contraband, and Dunston told Hernandez that he

was going to "step up a yard right now and see what it is."         This

meant, Agent Boyle testified, that Dunston intended to convert 100

grams of powder into crack.    Later that day, Dunston and Hernandez

spoke again.     When Hernandez asked, "how did that come out,"

Dunston replied that the result was "[a]ll yellow" and that he

"[g]ot back, like, 2 extra grams.      It was, like, 102 when it dried

all the way out, bone dry."    Boyle testified that the yellow tinge

of Dunston's product was emblematic of crack cocaine and that,

since   converting   powder   to    crack   requires   water,   Dunston's




                                   - 12 -
reference to drying the product was also consistent with making

crack.

             When judges sit as factfinders, they are not obliged to

put their common sense into cold storage.        Given the wiretaps and

Boyle's testimony, the district court surely had a rational basis

for   finding,   beyond   any    reasonable   doubt,   that   Dunston   was

responsible for at least 200 grams of crack stemming from the June

26 events.    For one thing, the court supportably could have found

Dunston responsible for the 100 grams that he himself cooked.           For

another thing, the court supportably could have found that the

remaining 100 grams, retained by Hernandez, was to be converted

from powder to crack as part of the conspiracy and that the

conversion was reasonably foreseeable to Dunston.1

             Dunston protests.     He says that there is no evidence

that this latter 100 grams of powder was actually converted to

crack and that this part of the district court's drug-quantity

calculation was faulty because it implicitly assumed that 100 grams

of powder cocaine, when converted, would yield 100 grams of crack




      1For example, the court heard evidence that once Dunston told
Hernandez that he "got back 2 . . . extra grams" after cooking the
powder, Hernandez responded, "You should have done mine." Dunston
replied, "You're the only one that didn't want me to do yours!"
and indicated that Hernandez had mentioned planning to cook his
powder in a particular type of pot. Several hours later, Hernandez
called a third party and asked to use his kitchen.


                                   - 13 -
cocaine.       He insists that, even in optimal conditions, 100 grams

of powder cannot be converted into more than 89.2 grams of crack.

               This attack misfires.     The court had before it evidence

that, on both June 26 and June 29 (discussed infra), Dunston

himself had performed conversion operations and had gotten better

than a one-to-one yield.            Given that evidence, the court was

entitled to apply a one-to-one conversion ratio in its appraisal

of the conspiracy's output.2

               The court also heard the particulars of a transaction

that occurred on June 29. On that date, the government intercepted

a call between Hernandez and a third party, during which Hernandez

bought 200 grams of powder cocaine.            Just over two hours later,

Dunston called Hernandez to inform him that he planned to "do the

whole thing together."         He subsequently reported that the result

was "206 wet," and yellow in color, but quickly turning white.

Given       this   evidence   and   Boyle's   explanatory    testimony,   the

district court could have attributed, beyond any reasonable doubt,

an additional 200 grams of crack to Dunston.                After all, proof




        2
        We note, moreover, that the statute of conviction
criminalizes conspiracies involving the possession and intended
distribution of "280 grams or more of a mixture or substance
. . . which contains cocaine base." 21 U.S.C. § 841(b)(1)(A)(iii)
(emphasis supplied).     Whether the weight of the defendants'
products came from pure crack cocaine or crack combined with water
or some other adulterant is beside the point: the record reflects
that the defendants conspired to possess and distribute a "mixture
or substance" that contained cocaine base. Id.


                                     - 14 -
beyond a reasonable doubt does not require proof to an absolute

certainty.    See United States v. Lasseque, 806 F.3d 618, 623 (1st

Cir. 2015), cert. denied, 136 S. Ct. 1472 (2016).

             Dunston counters that the government offered no direct

or tangible evidence that this batch of cocaine ever existed.       But

it is old hat that proof of a defendant's guilt can be based, in

whole or in part, on circumstantial evidence.         See United States

v. George, 841 F.3d 55, 63 (1st Cir. 2016); United States v.

Williams, 717 F.3d 35, 39-40 (1st Cir. 2013).         In this instance,

the district court, qua factfinder, drew a series of reasonable

inferences from the evidence, and its conclusion that Dunston was

responsible for this additional 200 grams of crack is unimpugnable.

             For these reasons, Dunston's conviction must stand.

             2.   Wooldridge.   The record also provides ample support

for the district court's decision to attribute at least 280 grams

of crack cocaine to Wooldridge.            Wooldridge was arrested with

ninety-three grams of crack on his person.        In addition, there was

cogent evidence that Wooldridge sold his codefendants the 200 grams

of powder cocaine mentioned in the June 26 conversation.             As

explained above, 200 grams of powder could be found, beyond a

reasonable doubt, to equal 200 grams of crack.              Because the

production of crack was a reasonably foreseeable act in furtherance

of the conspiracy, the district court did not err either in finding

that Dunston and Hernandez converted their shares of the powder


                                  - 15 -
sold by Wooldridge into crack or in holding Wooldridge responsible

for a corresponding amount of crack.      See Sepulveda, 15 F.3d at

1197.

          In an effort to stave off this conclusion, Wooldridge

insists that he was not yet part of the charged conspiracy when he

sold drugs to his codefendants at the end of June.         Building on

that foundation, he posits that any crack cocaine resulting from

that sale cannot be attributed to him.            This is revisionist

history, and we reject it.     Wooldridge pleaded guilty to being a

member of the conspiracy beginning in August of 2011 — long before

the sale occurred.    He is bound by his plea.    See United States v.

Laracuent, 778 F.3d 347, 351 (1st Cir.), cert. denied, 135 S. Ct.

2875 (2015).

          That ends this aspect of the matter.       We conclude that

the evidence was sufficient to allow the district court to find

beyond a reasonable doubt that at least 280 grams of crack were

attributable to Wooldridge.      Consequently, his conviction must

stand.

                       C.   Dunston's Sentence.

          Dunston's    claim    of   sentencing    error   is   easily

dispatched.    He does not challenge the district court's guideline

calculations but, rather, maintains that his 144-month sentence

offends the parsimony principle, see United States v. Sepúlveda-

Hernández, 817 F.3d 30, 34 (1st Cir. 2016) (citing 18 U.S.C.


                                - 16 -
§ 3553(a)), because it is greater than necessary to achieve the

purposes of sentencing.     Under our case law, we treat such a claim

as one of substantive unreasonableness.      See id.

          Dunston did not raise this claim in the district court,

and the standard of review is unsettled.        See United States v.

Ruiz-Huertas, 792 F.3d 223, 228 (1st Cir.) (noting uncertainty

with respect to standard of review regarding unpreserved claims of

substantive   unreasonableness),    cert.   denied,    136   S.   Ct.   258

(2015).   For simplicity's sake, we assume — favorably to Dunston

— that review is for abuse of discretion.

          Dunston was subject to the career offender guideline.

See USSG §4B1.1(a).    The court below set his guideline sentencing

range (GSR) at 262-327 months and sentenced him appreciably below

the bottom of that range.    A defendant who challenges a below-the-

range sentence as substantively unreasonable must carry a heavy

burden.   See United States v. Montero-Montero, 817 F.3d 35, 37

(1st Cir. 2016).      The greater the drop from the bottom of the

range, the heavier the lift.     See id.

          There is more than one reasonable sentence in any given

case, and the relevant inquiry is whether the sentence imposed

"resides within the expansive universe of reasonable sentences."

United States v. King, 741 F.3d 305, 308 (1st Cir. 2014).                In

mounting this inquiry, we concentrate on whether the sentence




                                - 17 -
reflects "a plausible . . . rationale and a defensible result."

United States v. Martin, 520 F.3d 87, 96 (1st Cir. 2008).

           The   court   below   supplied      a    plausible    rationale      for

Dunston's sentence.        It explained that a significant period of

incarceration was warranted to protect the public from future

crimes, provide deterrence, and punish the defendant.                Given the

scope and duration of the conspiracy, the force of this explanation

cannot be gainsaid.      The court added, though, that "incarceration

at or near the advisory guideline range seems to be more than what

is necessary to meet the goals of sentencing."               For that reason,

it executed a sharp downward variance.

           Despite the court's seeming leniency, Dunston assails

the result, arguing that his ultimate sentence was skewed by a

"mechanical application" of the career offender guideline.                     This

argument is constructed out of whole cloth: it overlooks the

undeniable fact that the sentencing court's downward variance was

anything but mechanical, yielding a sentence almost ten years below

the nadir of the guideline range.         The challenged sentence, which

took into account the nature of Dunston's crime, his history, and

his   personal   characteristics,       was   wholly    defensible       and   well

within the court's discretion.      See King, 741 F.3d at 309.

                      D.    Wooldridge's Sentence.

           Wooldridge      challenges    the       amount   of   crack    cocaine

attributed to him for sentencing purposes.             This drug quantity (at


                                  - 18 -
least 840 grams) is separate from the lesser drug quantity (280

grams) needed to establish Wooldridge's guilt.                      See supra Part

IIB.    We explain briefly why two distinct findings are necessary.

               At trial, the government had the burden of proving the

drug quantity charged as an element of the offense (280 grams or

more) beyond a reasonable doubt.              See Alleyne, 133 S. Ct. at 2155.

At sentencing, however, "a defendant-specific determination of

drug quantity [i]s a benchmark for individualized sentencing under

the guidelines."         Colon-Solis, 354 F.3d at 103.               The sentencing

court     is     charged      with    making        such   a     defendant-specific

determination.         See United States v. Correy, 773 F.3d 276, 279-

80, 280 n.4 (1st Cir. 2014).                  All drugs "attributable to[] or

reasonably foreseeable by" a defendant may be included in that

defendant's      individualized       total.        United      States   v.   Cintrón-

Echautegui, 604 F.3d 1, 5 (1st Cir. 2010).                     The government bears

the     burden    of    proving      drug     quantity     at    sentencing      by    a

preponderance of the evidence.               See id. at 6.

               The sentencing guidelines direct a sentencing court to

consider relevant conduct, see USSG §1B1.3(a), when assessing the

drug quantity for which a defendant is to be held accountable at

sentencing.       Where, as here, a defendant has been convicted as a

coconspirator, his relevant conduct includes not only his own acts

and    omissions       but   also    the    reasonably     foreseeable        acts    and




                                           - 19 -
omissions     of   other      coconspirators    in    furtherance      of     the

conspiracy.    See id. §1B1.3(a)(1)(B).

             A sentencing determination of defendant-specific drug

quantity does not require mathematical precision: it need only be

a   "reasonable    approximation    of   the   weight     of   the   controlled

substance(s) for which the defendant should be held responsible."

United States v. Demers, 842 F.3d 8, 12 (1st Cir. 2016).                    As we

have said, calculating drug quantities "is not an exact science,"

and the sentencing court "need not be precise to the point of

pedantry."     United States v. Platte, 577 F.3d 387, 392 (1st Cir.

2009).

             Such drug-quantity determinations are quintessentially

factual in nature, and we review them for clear error.                        See

Cintrón-Echautegui, 604 F.3d at 6.           That standard dictates that a

finding will stand unless a reviewing court, after assessing the

whole of the record, is firmly convinced that a mistake has been

made.    See id.   "[W]here there is more than one plausible view of

the circumstances, the sentencing court's choice among supportable

alternatives cannot be clearly erroneous."           United States v. Ruiz,

905 F.2d 499, 508 (1st Cir. 1990).

             Against   this    backdrop,     Wooldridge    argues     that    the

district court committed clear error in finding him accountable

for at least 840 grams of crack cocaine.             That finding, combined

with other uncontroversial guideline calculations and Wooldridge's


                                    - 20 -
designation as a career offender, see USSG §4B1.1(a), resulted in

a GSR of 262-327 months.    The district court proceeded to impose

a below-the-range sentence of 132 months.

          Although the district court varied downward from the

guideline range, any error in calculating that range would likely

be material on appeal.   See Molina-Martinez v. United States, 136

S. Ct. 1338, 1346 (2016) ("In most cases a defendant who has shown

that the district court mistakenly deemed applicable an incorrect,

higher Guidelines range has demonstrated a reasonable probability

of a different outcome.").    Here, however, the district court's

drug-quantity determination (and, thus, its configuration of the

GSR) is not clearly erroneous.

          The district court identified three transactions that

linked Wooldridge to well over 840 grams of crack cocaine.   First,

Wooldridge sold powder cocaine to Hernandez and Dunston at the end

of June and, as discussed above, see supra Part IIB, that sale

formed a solid basis for a finding attributing approximately 200

grams of crack cocaine to him.   Second, the court supportably tied

Wooldridge to a purchase of 300 grams of powder cocaine that

occurred on July 31.3    The record includes discussions among all

three defendants about the purchase and about their plans to




     3 Indeed, Wooldridge admits that the ninety-three grams of
crack cocaine found on his person when he was arrested was his
share of this purchase.


                               - 21 -
convert the powder into crack.        That evidence, coupled with the

court's permissible use of a one-to-one conversion ratio, was

sufficient to ground attribution of 300 grams of crack cocaine to

Wooldridge.

             Third, and finally, the court reasonably attributed an

additional 497 grams of crack cocaine to Wooldridge with respect

to events occurring on August 31.          At that time, federal agents

seized a package sent by Cruz (in Puerto Rico) to an acquaintance

of Hernandez (in Massachusetts).      The package was found to contain

497 grams of powder cocaine.      Although the evidence indicated that

Hernandez was the prime mover in arranging for the shipment, both

Wooldridge and Dunston encouraged his efforts. Thus, the 497 grams

of powder cocaine, destined for conversion into crack cocaine,

could fairly be attributed to Wooldridge for sentencing purposes.

See Cintrón-Echautegui, 604 F.3d at 5; USSG §1B1.3(a)(1)(B).

             The fact that the package was intercepted before its

contents reached the defendants is of no moment.         The record makes

manifest that the defendants, in furtherance of the conspiracy,

sought the shipment of powder cocaine as a prelude to conversion

and would in all probability have converted it to crack cocaine if

given the chance.       Indeed, the government introduced evidence

showing that, on no fewer than seven separate occasions between

June   and   August,   the   defendants    procured   powder   cocaine   and

converted it into crack cocaine within a matter of days.                 When


                                  - 22 -
drug traffickers have forged a well-defined pattern and practice

for their operations, a sentencing court need not turn a blind eye

to that pattern and practice.

             Wooldridge tries to distance himself from this drug

weight, asseverating that no part of the August 31 shipment should

be attributed to him because his coconspirators had "cut[] [him]

out of the picture" by then.        But the evidence of exclusion is

meager, and the district court was not obliged to resolve this

issue in Wooldridge's favor.      Just as withdrawal from a conspiracy

requires more than an empty claim of disaffection, see United

States v. Piper, 298 F.3d 47, 53 (1st Cir. 2002) (explaining that,

in order to withdraw, a conspirator must take affirmative action

to disavow or defeat the conspiracy), so too does a claim of

exclusion.      There is simply no credible evidence that either

Wooldridge or his partners in crime took any such action here.         To

the   contrary,   the   record   reflects   that   Wooldridge   contacted

Hernandez at the end of July in search of cocaine and exhibited an

abiding intent to remain involved in the conspiracy.            Given the

absence of any competent evidence of withdrawal, the sentencing

court did not clearly err in finding the coconspirators' acts at

the end of August to be a part of Wooldridge's relevant conduct.

                        E.   Hernandez's Sentence.

             Hernandez's claim of sentencing error similarly embodies

a challenge to the district court's drug-quantity determination.


                                  - 23 -
The court found him responsible for at least 2.8 kilograms of crack

cocaine.           Combined      with     other     uncontroversial        guideline

calculations and a career offender enhancement, this drug quantity

resulted in a GSR of 292-365 months.                 The district court imposed

a below-the-range sentence of 162 months.

             The record is replete with circumstantial evidence that

Hernandez headed up the conspiracy.                   He was involved in every

transaction that we have discussed: the events of June 26 (200

grams), the events of June 29 (200 grams), the events of July 31

(300   grams),      and    the   events    of     August   31   (497    grams).      In

consequence of this involvement, 1,197 grams of crack cocaine were

fairly attributable to him.

             Furthermore, the record contains proof sufficient to

support      the    attribution      to     Hernandez,      using      a   one-to-one

conversion ratio, of an additional 1,000 grams of crack cocaine:

      200 grams of powder cocaine purchased and converted on July

       7;

      100 grams of powder cocaine converted on July 15;

      500   grams    of    powder      cocaine    purchased    on     August   5   and

       converted the following day; and

      200 grams of powder cocaine purchased on August 28 and at

       least partially converted the next day.

When these quantities are combined with the nearly forty-four grams

of crack sold by Hernandez to undercover officers at the start of


                                         - 24 -
the probe, Hernandez can properly be held responsible for a minimum

of 2.2 kilograms of crack cocaine.

                To boost that total to 2.8 kilograms, the district court

reasonably relied on two additional events.                 First, the evidence

showed that, on July 29, Hernandez arranged the payment of $19,000

to   Cruz       for   powder   cocaine    previously     supplied.      The   court

supportably concluded that this payment represented the purchase

of roughly 500 grams of powder cocaine.                See Sepulveda, 15 F.3d at

1201 (holding that when cash is likely dedicated to the purchase

of contraband, "a sentencing court may convert the cash into

equivalent amounts of narcotics" for sentencing purposes).                    After

applying a one-to-one conversion ratio, this transaction yielded

500 grams of crack cocaine attributable to Hernandez.

                The court reasonably added another 100 grams, based on

evidence that Hernandez was actively dealing crack cocaine between

January and June (when the wiretaps were instituted).                  While this

finding represented an estimate, it was by all odds a conservative

estimate — especially since Hernandez pleaded guilty to conspiring

to deal crack as early as August of 2011.                  We have consistently

upheld      a    sentencing    court's    use     of   reasonable    estimates   in

assessing drug quantity, see, e.g., United States v. Bernier, 660

F.3d 543, 546 (1st Cir. 2011); Platte, 577 F.3d at 392; United

States v. Ventura, 353 F.3d 84, 88 (1st Cir. 2003), and that praxis

has particular appeal when — as in this case — the sentencing


                                         - 25 -
court,   in    fashioning   its   estimate,    has   taken   a   conservative

approach, cf. United States v. Sklar, 920 F.2d 107, 113 (1st Cir.

1990) (admonishing sentencing courts, in this context, to "err on

the side of caution" (citation omitted)).

              This gets the grease from the goose.           While we could

analyze these multiple transactions in more granular detail, doing

so would serve no useful purpose.            It suffices to say that the

record discloses ample evidence to ground a finding that Hernandez

was responsible for at least 2.8 kilograms of crack cocaine.              As

a result, we discern no clear error in the district court's drug-

quantity determination.

              Hernandez has one last string to his bow. He takes issue

with the district court's designation of him as a career offender

under the sentencing guidelines.            Specifically, he asserts that

the court improperly relied, over objection, on a portion of his

presentence      investigation    report,    which   cited   only   criminal

offender record information (CORI) to lay out his criminal history.

              The government bears the burden of establishing the

existence of at least two predicate offenses to trigger a career

offender enhancement under the sentencing guidelines.             See United

States v. Bryant, 571 F.3d 147, 153 (1st Cir. 2009) (citing USSG

§4B1.1(a)).      The government may carry this burden in divers ways,

such as by furnishing "a certified copy of the conviction or an

equivalent proffer" or by pointing to official court documents of


                                   - 26 -
the type that engender a presumption of reliability.            Id. at 153,

155 (quoting United States v. McKenzie, 539 F.3d 15, 19 (1st Cir.

2008)).     But anecdotal CORI descriptions, if objected to, are not

enough.     See id. at 154-55; cf. United States v. Brown, 510 F.3d

57, 74 (1st Cir. 2007) (observing that "when a defendant challenges

a conviction laid out in the [presentence investigation report],

more is required").

             At Hernandez's sentencing, the government argued for a

career    offender   enhancement    noting   that     the   CORI    material

described in the presentence investigation report identified three

potential predicate offenses.       Hernandez objected.       The district

court stayed the proceedings to give the government the opportunity

to make a more persuasive evidentiary proffer; but when the

government produced nothing more, the court overruled Hernandez's

objection and sentenced him as a career offender.

             On appeal, Hernandez insists that the record before the

district court was insufficient to show the required predicate

offenses.    The government concedes this point and instead proffers

a series of docket sheets, never made available to the district

court, inviting us to take judicial notice of them.           These docket

sheets, it says, will confirm the existence of the required

predicate     offenses   (albeit   belatedly)   and    render      any   error

harmless.




                                   - 27 -
              We decline the government's invitation.          As a general

matter, we do not consider evidentiary materials that were not

proffered in the district court.             See United States v. Farrell,

672 F.3d 27, 30-31 (1st Cir. 2012); United States v. Kobrosky, 711

F.2d 449, 457 (1st Cir. 1983). Although we have occasionally taken

judicial notice of state court documents identified for the first

time on appeal, see, e.g., Farrell, 672 F.3d at 31; United States

v. Mercado, 412 F.3d 243, 247-48 (1st Cir. 2005), we cannot do so

here.   The proffered documents bear no hallmarks of authenticity

and, in all events, are subject to interpretation.                  A career

offender designation can expose a defendant to a significantly

higher sentence, and it remains the district court's duty to ensure

that documents offered to prove the existence of predicate offenses

are "sufficiently reliable."       Bryant, 571 F.3d at 154.

              Although we conclude that the district court erred, we

think   it    would   be   premature   to    vacate   Hernandez's   sentence.

Instead, we remand so that the district court may hold a hearing

and afford the parties an opportunity to present evidence anent

Hernandez's prior convictions.          Should the district court find

that    the    evidence    presented    is     sufficiently   reliable    and

establishes the existence of the requisite number of predicate

offenses, it should, within sixty days from the date hereof, report

its findings and conclusions to this court. If, however, the court

finds to the contrary, it should, within sixty days from the date


                                   - 28 -
hereof, report its findings and conclusions to this court and

proceed to vacate Hernandez's sentence and resentence him without

reference to the career offender guideline.

III.   CONCLUSION

           We need go no further. For the reasons elucidated above,

we affirm the judgment in appeal number 15-1812, thus affirming

Dunston's conviction and sentence. We likewise affirm the judgment

in appeal number 15-2000, thus affirming Wooldridge's conviction

and sentence.   With respect to appeal number 15-1999 (Hernandez),

we remand for further proceedings consistent with this opinion and

for the time being retain appellate jurisdiction over this appeal.



So ordered.




                              - 29 -
