                            In the
United States Court of Appeals
              For the Seventh Circuit
                         ____________

Nos. 00-4184 & 00-4214
UNITED STATES OF AMERICA,
                                               Plaintiff-Appellee,
                                v.

DANNY SMITH and HARRY D. LOWE,
                                    Defendants-Appellants.
                         ____________
           Appeals from the United States District Court
      for the Northern District of Illinois, Western Division.
         No. 99 CR 50022—Philip G. Reinhard, Judge.
                         ____________
  ARGUED OCTOBER 23, 2001—DECIDED OCTOBER 16, 2002
                    ____________


  Before HARLINGTON WOOD, JR., CUDAHY, and KANNE,
Circuit Judges.
  CUDAHY, Circuit Judge. Harry Lowe and Danny Smith
were convicted by a jury of several counts of conspiracy
and possession of marijuana with intent to distribute, in
violation of 21 U.S.C. §§ 841, 846. During the tax years
in question, Lowe had substantial income, presumably
from drug trafficking, which he failed to report as in-
come, in violation of 36 U.S.C. § 7203. The defendants
appeal on several grounds related to whether they were
given a fair trial and whether the district court erred
in determining their criminal sentences. We affirm.
2                                  Nos. 00-4184 & 00-4214

                            I.
  This appeal involves two criminal defendants and nu-
merous alleged errors by the district court. Therefore,
we must discuss the facts of the case in some detail.
This narrative follows a simple chronology: the drug trans-
actions leading to Harry Lowe’s arrest, the events leading
authorities to Danny Smith, the seizure of a large amount
of cash from Lowe’s residence (which forms the subject of
his tax crimes) and the subsequent trial and sentencing
proceedings.


                            A.
  The conspiracy charges against defendants Lowe and
Smith arise from several drug transactions that took
place from the early to the late 1990s. They can be sepa-
rated into four episodes: (1) the purchase of marijuana
from Jose Rubalcava; (2) the purchase of marijuana from
Gerardo Rivera via co-conspirator Edwin Rivas; (3) the
purchase of marijuana in a deal Rivas brokered with sup-
pliers in Texas and Mexico and (4) the purchase of mari-
juana from a supplier in Arizona.


    1. Marijuana from Rubalcava.
   In the early 1990s, a home remodeler named Stuart
Swick, a co-conspirator and eventual prosecution witness,
was working at the home of his friend Harry Lowe, a.k.a.
Wayne Lowe, the owner of a used car lot. Swick and Lowe
discussed one of Swick’s other clients, Jose Rubalcava.
Swick had observed Rubalcava moving garbage bags
from the trunk of his car into his home, and Swick in-
ferred that Rubalcava was trafficking in marijuana. This
piqued Lowe’s interest, and he asked Swick to find out
if Rubalcava would be willing to sell him several pounds
Nos. 00-4184 & 00-4214                                   3

of marijuana, and if so, at what price. According to testi-
mony at trial, a deal was struck for five pounds of mari-
juana (approximately 2.3 kilograms) for $5,000. Several
weeks later, Lowe gave Swick $10,000 to arrange anoth-
er deal with Rubalcava, this time for ten pounds of mari-
juana (about 4.6 kilograms).
  During 1992, Lowe and Swick continued to make pur-
chases from Rubalcava. Swick observed that some of
the cash supplied by Lowe came from a safe buried in
the dirt floor of Lowe’s basement. In the summer of 1992,
Lowe enlisted his cousin, Tom Lones, in a plan to make
a $50,000 “down payment” on 300 pounds (140 kilograms)
of marijuana from Rubalcava, never intending to pay
the balance. The plan failed when Rubalcava delivered
the first 90 pounds but refused to deliver any more until
he was paid. Apparently, the buyers ceased dealing with
Rubalcava from that time forward.


 2. Marijuana purchased from Rivera.
  Lowe had another opportunity to traffic in large quanti-
ties of marijuana in 1994. According to testimony at trial,
the business manager for Lowe’s car lot, Greg Fitzgerald,
met a customer named Edwin Rivas. Fitzgerald found
out that Rivas had acquaintances in the drug importa-
tion business and set up a meeting between Lowe and
Rivas. At the meeting, Lowe asked Rivas if he knew of
any sources for marijuana or cocaine, and Rivas con-
tacted Gerardo Rivera on Lowe’s behalf. Thereafter,
Rivas acted as a courier for Lowe, exchanging large
amounts of cash for marijuana. The first transaction was
for 50 pounds (or 23 kilograms) at $35,000, and Rivas
was usually given $300 to $400 for his efforts.
4                                 Nos. 00-4184 & 00-4214

    3. Marijuana from Texas and Mexico.
  In the summer of 1994, Lowe asked Rivas to go to Lare-
do, Texas, and negotiate a deal with a Spanish-speaking
marijuana source. Rivas agreed. Once in Laredo, Rivas
met with two individuals and negotiated a deal to acquire
50 kilograms of marijuana for $475 per kilogram. Rivas
contacted Lowe, who accepted the deal. Rivas then re-
turned to Rockford, picked up $23,000 from Lowe, and
brought it to Texas. The first shipment of marijuana ar-
rived in Rockford a short time later.
  Following this transaction, Rivas traveled to Laredo
again, this time accompanied by Lowe. They were taken
to Mexico and introduced to a person called “Rogilo” with
whom they negotiated new terms. The deal made at
that meeting set up a regular shipment of 300 pounds
(about 140 kilograms) of marijuana to Rockford at $275
per pound ($605 per kilogram, or about $82,000 per ship-
ment). According to testimony at trial, this arrange-
ment resulted in approximately ten 300-pound shipments
of marijuana to Rockford between 1994 and 1996.
  The marijuana was transported by sealing it in the gas-
oline tanks of pick-up trucks. The trucks were driven
to Rockford, where the drivers would stay at a local ho-
tel. Lowe would drive the trucks from the hotel to
his dealership or to an auto body shop owned by his
friend (and co-defendant) Danny Smith. They would re-
move the gas tanks and cut them open to access the
marijuana. Containers filled with payments of $100,000 or
more were then welded inside new tanks, which in turn
were installed on the trucks and returned to the drivers.
Danny Smith’s business partner at the body shop, James
Petrow, who subsequently testified at trial, witnessed
this activity several times, and once assisted Smith in
dividing marijuana into smaller units and packaging it
in bags. The bags were kept in a freezer at the rear of
Nos. 00-4184 & 00-4214                                   5

the body shop, and buyers would periodically stop by to
pick up marijuana and drop off money.


 4. Marijuana from Arizona.
  In November of 1995, Rivas bought a van from Lowe’s
lot. A few months later, Lowe asked Rivas to drive the
van to Arizona to pick up some marijuana. Rivas again
agreed. He drove the van to a hotel in Tucson, where
Lowe’s contact picked up the van to load it with drugs.
The van was returned the next day and Rivas was
shown how marijuana had been hidden behind the
van’s interior rear panels. On the return trip, the Nebras-
ka State Police stopped Rivas. Rivas consented to a search,
and a trooper found 115 pounds of marijuana (about 50
kilograms). Rivas was then placed under arrest.
  Rivas agreed to cooperate with DEA officials. The DEA
sent Rivas on a controlled delivery to Lowe’s car lot,
using recording and surveillance equipment. Rivas pulled
into the garage of Lowe’s facility, showed Lowe how
the marijuana could be accessed, and asked to receive
one pound of marijuana in partial payment of his $5,000
courier fee. Rivas then borrowed a car from Lowe and
drove a short distance, where he turned over the mari-
juana and a recording device to DEA agents. Shortly
thereafter, Lowe left the car lot. However, because he was
driving very fast, DEA agents were unable to follow. Lowe’s
vehicle was subsequently found outside Danny Smith’s
auto body shop, but when Lowe left the lot, he once again
drove too fast for authorities to maintain surveillance.
That evening, Lowe was finally arrested as he left a tav-
ern owned and operated by his father. A search war-
rant was obtained to search Lowe’s car lot facilities. The
search recovered 63 packages suspected of containing
drugs, 52 of which were chemically tested and determined
to contain marijuana weighing 35 kilograms (about 75
6                                   Nos. 00-4184 & 00-4214

pounds). A loaded shotgun was on the premises and ac-
cessible at the time of the search.

                             B.
  Lowe was released on bond shortly thereafter. Smith
and Lowe still possessed large amounts of marijuana,
which Smith placed in the trunk of a Saab at the body
shop. The auto body shop had purchased the Saab from
Lowe’s car lot. One week after Lowe’s arrest and release,
Lowe asked Swick to do him a favor and to get instruc-
tions from Smith. Smith directed Swick to pick up the
Saab at the auto body shop and to lock it in Swick’s ga-
rage. Eventually, Smith also directed Swick to remove
a marijuana-filled duffle bag from the trunk of the Saab
and to lock it in a freezer that was also located inside
the garage. Periodically over the next year, Lowe would
direct Swick to transport quantities of this marijuana
to Smith’s body shop. On one occasion in March of 1997,
Swick delivered nine pounds to Smith.
   In April 1997, the police department of Loves Park,
Illinois, received a tip that Swick was storing a large quan-
tity of marijuana in a freezer at his residence. The police
then visited Swick’s home, and Swick voluntarily agreed to
a search. Both Swick and Tom Lones, who was Lowe’s
cousin and the owner of Swick’s rented home, disclaimed
ownership of the locked freezer in the garage. The authori-
ties impounded the freezer and transported it to State
Police headquarters. It was then opened and found to
contain almost 18 pounds of marijuana. A fingerprint
examiner inspected the packages of marijuana, finding
Lowe’s fingerprints on one and Smith’s on another.

                             C.
  On December 3, 1997, a search warrant was executed
at Lowe’s residence, simultaneously with the execution
Nos. 00-4184 & 00-4214                                     7

of a seizure warrant based on a civil forfeiture complaint.
Several documents were seized, including some items
that were improperly catalogued.1 In addition to numer-
ous firearms, Police seized a safe buried in the basement
floor, of which Lowe denied knowledge. The safe con-
tained more than $100,000 in cash. Although Lowe had
earned income during 1995 and 1996, he did not file tax
returns for those years until December 12, 1997, shortly
after the search and seizure.
  According to testimony at trial, Lowe approached Vin-
cent Lloyd, an accountant, in March of 1998 for his assis-
tance in reviewing and correcting his tax returns as far
back as 1993. The Government asserts that because this
review and correction took place so soon after the search
and seizure, they raise a legitimate suspicion that Lowe
was trying to protect some of his assets from forfeiture.


                             D.
   Smith and Lowe were indicted by a federal grand jury
in June 1999. Count 1 charged both Smith and Lowe
with conspiring to distribute in excess of one hundred kilo-
grams of marijuana, a Schedule I Controlled Substance,
in violation of 21 U.S.C. § 841(a)(1). Counts 2 and 3
charged Lowe with conspiracy to distribute “approximately
fifty-two kilograms” and “approximately 1038 grams” of
marijuana, respectively. Counts 4, 5 and 6 charged Lowe
with making false statements on his tax returns for 1994,




1
  The apparent lack of orderly police procedure with respect
to certain documents seized from Lowe’s home forms the basis
for Lowe’s unsuccessful “chain of custody” argument discussed
in Section II.A.3, infra.
8                                    Nos. 00-4184 & 00-4214

1995 and 1996, in violation of 26 U.S.C. § 7606(1).2 Counts
7 and 8 charged Lowe with willful failure to file timely
tax returns for 1995 and 1996, in violation of 26 U.S.C.
§ 7206(1). A jury trial followed.
   Before the government commenced its case, Lowe ob-
jected to joinder of the tax and drug charges. Lowe ar-
gued that these charges were unrelated and should be
severed to avoid unfair prejudice. The district court de-
nied the motion for severance and the trial went for-
ward.3 After the government presented its case-in-chief
against Lowe but before Lowe began his defense case,
the district court informed counsel for Smith that any
cross examination by him of Lowe’s defense witnesses
would be limited to matters that pertained to his client,
Danny Smith. The district court judge said that he
wanted to avoid jury confusion by limiting the possi-
bility that counsel for Smith would attempt to develop
his own case during the cross examination of Lowe’s
defense witnesses. Instead, counsel for Smith was in-
structed that he could explore a broader line of inquiry
if he called these witnesses for direct examination dur-
ing his client’s defense. Counsel for Smith then consented
to this procedure.
  Testifying in his own defense, Lowe stated that his trip
to Texas with Rivas was merely to repossess a car he
had sold, and that his sponsorship of Rivas’ trip to Arizona
was merely a gesture intended to benefit Rivas. Upon
Rivas’ return to Rockford, Lowe testified that Rivas left
his van at the car lot for repair. Lowe also denied any
drug trafficking with Swick and claimed that the red


2
   On the government’s motion, Count 4 was dismissed prior to
trial, and Counts 5 and 6 were dismissed during trial.
3
  As the government points out, Lowe did not renew his objection
at the close of evidence.
Nos. 00-4184 & 00-4214                                    9

Saab in fact belonged to Danny Smith’s auto body shop
and was used primarily by James Petrow. Lowe also
testified that he failed to file returns for 1995 and 1996
because he had fallen behind in the early 1990s, was afraid
of the consequences and did not know how to correct
the situation. Danny Smith subsequently testified that
James Petrow was his business partner in the auto body
shop business from October 1993 to March 1997. At that
time, Petrow’s irresponsibility with money had caused the
business to struggle. According to Smith, Petrow with-
drew business funds for personal use, thus putting the
shop itself in a precarious financial situation. When the
business partnership ended, Smith changed the locks at
the body shop. Smith also testified that he had never
engaged in drug trafficking, that he had never seen
Edwin Rivas before trial and that he had never seen
pickup trucks with marijuana in the gas tanks at his body
shop. Smith did admit that he, with Lowe and Lones,
once passed around one-pound packages of marijuana at
Swick’s house. Smith also conceded that he had smoked
marijuana with Lowe and Lones, but he denied any in-
volvement with or knowledge of the marijuana found in
Swick’s freezer.
  Swick testified as well, and claimed that a written state-
ment made by him and furnished to the authorities was
based entirely on his own recollection and was written in
his own words. Lowe attempted to impeach Swick by
pointing out that the introductory paragraph of Swick’s
statement was substantially similar to a statement writ-
ten by an investigating agent. The trial court refused
to allow that line of questioning on cross, but evidence
that the two statements were similar was introduced,
with the agent admitting that the language was “boiler-
plate.”
  At one point during Petrow’s testimony, the government
asked if he remembered Lowe’s arrest, referring to the
10                                      Nos. 00-4184 & 00-4214

arrest for the charges in the present case. Petrow’s an-
swer referred to an arrest in Kentucky. The district
court immediately ordered that the reference to Kentucky
be stricken from the record, and the trial went on, not-
withstanding a motion by Lowe for a mistrial.
  On August 8, 2000, the jury convicted Smith and Lowe
of conspiracy to possess with intent to distribute mari-
juana, in violation of 21 U.S.C. § 846. Lowe was also
convicted of possession with intent to distribute mari-
juana, and distribution of marijuana, in violation of 21
U.S.C. § 841(a), and of willfully failing to file timely tax
returns for 1995 and 1996, in violation of 26 U.S.C.
§ 7206(1). The jury also completed a special verdict form,
which asked them to find the quantity of marijuana
involved by selecting a weight range. The ranges on the
form coincided with the ranges contained in 21 U.S.C.
§ 841(b)(1).4 The jury selected 50 to 100 kilograms of
marijuana for Lowe, and less than 50 for Smith. The
indictment, however, specified marijuana amounts in ex-
cess of 1200 kilograms for Lowe and in excess of 100 kilo-
grams for Smith.
   At sentencing, the trial court found that Lowe’s rele-
vant conduct involved 528 kilograms of marijuana, and
Smith’s relevant conduct involved more than 100 kilograms.
The court also made several findings that aggravated
Lowe’s sentence. U.S.S.G. §§ 2D1.1(b)(1) (presence of
firearm), 3B1.1(a) (leadership role), 3C1.1 (obstruction),
4A1.1 (criminal history). Both defendants were sentenced


4
  21 U.S.C. § 841(b)(1) varies the sentence for violation of § 841(a)
according to the type and amount of the drugs involved in the
violation. For marijuana, the ranges are: (A) 10 years to life for
over 1000kg; (B) 5 to 40 years for 100 to 1000kg; (C) 20 years
or less for 50 to 100kg and (D) five years or less for less than
50kg.
Nos. 00-4184 & 00-4214                                 11

at the statutory maximum for the applicable drug range
under § 841(b)(1). Smith was sentenced to 60 months in
prison, which is the statutory maximum for an amount
of marijuana less than 50 kilograms, § 841(b)(1)(D), and
Lowe received 240 months, which is the statutory maxi-
mum for an amount of marijuana between 50 and 100
kilograms, § 841(b)(1)(C). The cases were consolidated in-
to the matter now before the court. This appeal follows.


                           II.
  Lowe and Smith make several claims on appeal with
Lowe presenting eight issues and Smith presenting two.
Since many of these issues are related, we have once
again organized our discussion chronologically. We first
turn to both defendants’ appeals from the district court’s
actions at trial, and then to issues related specifically
to sentencing.


                           A.
   Lowe argues that the district court made the follow-
ing errors at trial. First, he claims that the tax charges
should have been severed from the conspiracy charges
and tried separately. Second, he asserts that he should
have been allowed to cross-examine Stuart Swick by dem-
onstrating the similarity between his statement and
an affidavit of Agent White. Third, he challenges the suf-
ficiency of the chain of custody for documents seized pur-
suant to the search warrant, and questions wheth-
er they can be properly admitted into evidence. Fourth, he
claims that a mistrial was necessary because James
Petrow testified that Lowe was arrested in Kentucky.
Finally, Lowe argues that the jury instructions created
an impermissible risk that the jury’s decision was not
unanimous. Smith’s only issue arising from the trial is
12                                  Nos. 00-4184 & 00-4214

his claim that the district court improperly hindered his
right to cross-examine Lowe and other witnesses who
were testifying during Lowe’s case-in-chief.


  1. Motion to sever.
  Lowe claims that the district court erred in denying
his motion to sever the tax counts. We review for abuse
of discretion the district court’s decision to deny a motion
to sever the counts of an indictment. See United States
v. Stokes, 211 F.3d 1039, 1042 (7th Cir. 2000).
  Before trial, Lowe moved to sever the tax charges
from the conspiracy charges, claiming that the evidence
used to support the tax counts would unfairly prejudice
the jury with respect to the drug charges. The trial court
denied the motion, and Lowe did not renew his objection
at the close of evidence. Citing case law that addresses
the issue of severing criminal co-defendants, the govern-
ment argues that Lowe waived any right he may have
had to severance by failing to renew his motion to the
district court. See, e.g., United States v. Phillips, 239 F.3d
829, 838 (7th Cir. 2001) (stating that, in the context of
co-defendants, “a motion for severance is typically waived
if it is not renewed at the close of evidence, primarily
because it is then that any prejudice which may have
resulted from the joint trial would be ascertainable”)
(quotations omitted); United States v. Cooper, 942 F.2d
1200, 1205 (7th Cir. 1991) (same); United States v. Caudill,
915 F.2d 294, 298 (7th Cir. 1990) (same). Lowe maintains,
however, that unlike a motion for severance of defen-
dants, where the actual content and effect of testimony
is largely unknown until it is presented, the documen-
tary evidence that formed the basis for the tax counts
could be fully assessed prior to trial. Therefore, a renewal
of his original objection was unnecessary. Although Lowe
Nos. 00-4184 & 00-4214                                     13

fails to cite any authority to support his position, his
reasoning is at least plausible.
  Nevertheless, we need not squarely address this issue
because Lowe’s substantive argument on severance
clearly fails on the merits. Under Rule 14 of the Federal
Rules of Criminal Procedure, a district court has discre-
tion to order separate trials if it appears that a defendant
will be prejudiced by trying the offenses together. Sev-
eral factors reduce or eliminate the prejudicial effect
of evidence, including the mutual admissibility and weight
of the evidence at issue. See, e.g., United States v. Traeger,
289 F.3d 461, 473 (7th Cir. 2002) (ruling that “mutually
admissible” evidence—i.e., evidence that is admissible
for either charge—is not prejudicial) (citing United States
v. Dijan, 37 F.3d 398, 402 (8th Cir. 1994)); United States
v. Freeland, 141 F.3d 1223, 1227 (7th Cir. 2000) (ruling
that potential inference of criminal personality is not un-
fairly prejudicial when there is sufficient evidence
to support all counts and the jury is instructed to con-
sider the counts separately). In the interest of preserving
judicial resources, a motion to sever should be granted
only when there is a serious risk of unfair prejudice that
deprives the defendant of a fair trial. Stokes, 211 F.3d
at 1042; United States v. Archer, 843 F.2d 1019, 1021
(7th Cir. 1988); Fed. R. Crim. P. 14 (giving district court
discretion to sever in order to avoid unfair prejudice to
the defendant). We give “great deference” to the district
court’s decision as to the hazards of a joint trial. Phillips,
239 F.3d at 838; see also United States v. Moore, 115 F.3d
1348, 1361-62 (7th Cir. 1997) (stating that defendant
bears “an extremely difficult burden” in showing that
a district court abused its discretion when denying a Rule
14 motion to sever) (quoting United States v. Moya-Gomez,
860 F.2d 706, 754 (7th Cir. 1988)).
  The evidence presented in Lowe’s case is not prejudi-
cial because it was “mutually admissible” for either the
14                                  Nos. 00-4184 & 00-4214

tax or drug charges. See United States v. Quilling, 261
F.3d 707, 715 (7th Cir. 2001) (holding that “ ‘prejudice re-
quiring severance is not shown if evidence on the sev-
ered counts would be admissible in the trial of the re-
maining counts’ ”) (quoting United States v. Rogers, 475
F.2d 821, 828 (7th Cir. 1973)); accord United States v.
Windom, 19 F.3d 1190, 1198 (7th Cir. 1994). Here, in an
effort to prove that Lowe had unreported income, the
government offered evidence of Lowe’s assets amounting to
an estimated $2.6 million, including cars, boats, real
estate, recreational vehicles, home improvements and
cash. The value of his assets and his lifestyle exceeded what
might be achievable from Lowe’s legitimate income from
the used car lot. Lowe claims that the evidence of his
wealth, presented to support the tax charges, would lead
the jury to impermissibly consider it as evidence of a
propensity for trafficking in drugs.
  But it is well settled in this circuit that evidence of
an unexplained, lavish lifestyle is probative of the exis-
tence of income derived from a drug conspiracy. See United
States v. Penny, 60 F.3d 1257, 1263 (7th Cir. 1995) (ruling
that “evidence of unexplained wealth is probative and
therefore admissible if it creates a reasonable inference of
the defendant’s involvement in the drug conspiracy or
trafficking”) (internal quotations omitted); Hogan, 886 F.2d
at 1507 (ruling that jury decides whether a defendant’s
wealth came from a legitimate income or criminal activ-
ity and that tax count can be joined with the criminal
conduct count involving the source of the wealth). Even if
the evidence might also suggest to a jury something ad-
verse about Lowe’s character, this evidence is admissi-
ble; it is circumstantially admissible to support an infer-
ence that Lowe had income from drug trafficking. The
disputed tax evidence here was “mutually admissible,” or
overlapping, in that the government could have pre-
sented evidence of Lowe’s extravagant lifestyle to sup-
Nos. 00-4184 & 00-4214                                   15

port the drug conspiracy charges. Therefore, the denial of
severance was not unfairly prejudicial nor an abuse of
discretion.
  Finally, the government voluntarily dismissed several of
the tax-related counts after providing the evidence to
support them. Lowe argues that this maneuver by the
government gives weight to the thesis that the prosecu-
tion of the tax counts was a mere pretense or ruse to
get Lowe’s assets before the jury. But the government
had a legitimate reason for dismissing some of the tax
charges: it would have been difficult to pursue them be-
cause Lowe failed to produce essential documents in a
timely fashion. Lowe cannot claim that the tax charges
were a sham when he made a contribution to the need
to dismiss them. The district court did not abuse its dis-
cretion in denying the motion for severance.


  2. Cross examination of Swick.
  Lowe argues that the district court abused its discre-
tion when it refused to let Lowe’s counsel use an officer’s
affidavit to impeach Stuart Swick during cross examina-
tion. In this case, an affidavit by law enforcement agent
John White had a first paragraph that was virtually
identical to an affidavit made by Swick, purportedly
from memory. At trial, Swick testified that he created
his statement entirely from his own recollection, and in his
own words, and that he did not use any notes or other
materials to compose his statement. Lowe’s counsel
wanted to impeach Swick with the White affidavit to
demonstrate that Swick was being untruthful about
the originality of his statement. The larger point he
was attempting to make was that Swick, a member of
the drug conspiracy, was motivated to lie about the con-
duct of other defendants in order to obtain a more favor-
able plea bargain.
16                                  Nos. 00-4184 & 00-4214

  Ordinarily, a district court’s evidentiary rulings are
reviewed for abuse of discretion. United States v. Aldaco,
201 F.3d 979, 985 (7th Cir. 2000). However, when the
restriction implicates the criminal defendant’s Sixth
Amendment right to confront witnesses against him,
which Lowe alleges here, the standard of review becomes
de novo. United States v. Cavender, 228 F.3d 792, 798 (7th
Cir. 2000); United States v. Sasson, 62 F.3d 874, 882 (7th
Cir. 1995).
  In general, the district court has wide latitude to im-
pose limitations on cross examination. Delaware v. Van
Arsdall, 475 U.S. 673, 679 (1986); Sasson, 62 F.3d at
882. Limitations on cross examination rise to the level of
a Sixth Amendment violation when they prevent the
exposure of a witness’s bias and motivation to lie. Van
Arsdall, 475 U.S. at 678-79. So long as the accused is
given the opportunity to expose bias, further cross exam-
ination is at the discretion of the district court. Sasson, 62
F.3d at 882 (stating that a core goal of cross examina-
tion is to expose bias); United States v. Nelson, 39 F.3d
705, 708 (7th Cir. 1994) (stating that if the defendant
is given the opportunity during cross examination “to
expose a motive to lie, it is of peripheral concern to the
Sixth Amendment how much opportunity defense coun-
sel gets to hammer that point home to the jury”); United
States v. Robinson, 832 F.2d 366, 373 (7th Cir. 1987) (rul-
ing that district court may preclude “cumulative and
confusing cross examination into areas already suffi-
ciently explored to permit the defense to argue personal
bias and testimonial unreliability”); see also Cavender,
228 F.3d at 798 (ruling that the district court can limit
cross examination to prevent, among other things, repeti-
tive or marginally relevant interrogation).
 Here, Lowe was given ample opportunity to expose bias.
Swick repeatedly testified that his written statement
Nos. 00-4184 & 00-4214                                  17

was entirely his own. During Lowe’s defense case, Lowe
was able to call Agent White to the stand and elicit
from him that, except for names, the same “boilerplate”
language that Swick claimed as his own was included
in Rivas’ May 18, 1999, statement, Petrow’s grand jury
statement and Agent White’s December 1997 affidavit. The
court also permitted Lowe to argue to the jury that
Swick lied about the preparation of the statement. Be-
cause Lowe was given ample opportunity to present
issues of credibility and potential bias to the jury, fur-
ther cross examination of Swick on the content of Agent
White’s affidavit was unnecessary. Further, the point
of similarity applied only to the introductory paragraph
of the two statements, not to its remaining substance.
Hence, it was of only marginal significance. The district
court’s ruling is sustainable on either a de novo or an
abuse of discretion standard.


 3. Chain of custody.
  Lowe next asserts that the chain of custody for docu-
ments seized at his residence during the execution of the
search warrant was so imperfect as to require denial of
their admission into evidence. The thrust of Lowe’s ar-
gument here is that these documents, which include self-
authenticating receipts and communications, were not
properly catalogued and could not be identified by the
agents who conducted the search. Therefore, he believes
that he is entitled to a new trial. We note at the outset
that a district court’s evidentiary rulings, including mat-
ters pertaining to the chain of custody, are reviewed
for abuse of discretion. United States v. Scott, 19 F.3d
1238, 1244 (7th Cir. 1994).
   Despite Lowe’s protestations to the contrary, we be-
lieve that the defects pointed to by Lowe are relatively
minor and do not raise serious issues of reliability. The
18                                 Nos. 00-4184 & 00-4214

general standard for admissibility of evidence is that it
be “in substantially the same condition as when the
crime was committed.” United States v. Aviles, 623 F.2d
1192, 1197 (7th Cir. 1980). A perfect chain of custody is
not a prerequisite to admission. See United States v.
Brown, 136 F.3d 1176, 1181 (7th Cir. 1998) (ruling that
“lack of proof regarding a chain of custody does not ren-
der [audio]tapes inadmissible”); United States v. Lott, 854
F.2d 244, 250 (7th Cir. 1988) (ruling that “the govern-
ment need not prove a perfect chain of custody for evi-
dence to be admitted at trial”). Unless the defendant
can point to evidence that specifically raises the issue
of tampering, a presumption of regularity attaches to
evidence that has at all times been kept in official
custody, and any gaps in the chain of custody go to the
weight of the evidence, not to its admissibility. See United
States v. Rivera, 153 F.3d 809, 812 (7th Cir. 1998); Brown,
136 F.3d at 1181 (“[M]erely raising the possibility (how-
ever hypothetical) of tampering is not sufficient to ren-
der evidence inadmissible.”). The documents in question
here were in official custody at all times, and Lowe does
not argue that they were no longer in their original con-
dition, nor that they had been tampered with or were
otherwise tainted. Therefore, the presumption of regu-
larity attaches. The district court’s chain of custody rul-
ing is affirmed.


  4. Motion for a Mistrial.
  Lowe argues that the district court erred when it re-
fused to grant him a new trial after Petrow made a refer-
ence to Lowe’s arrest in an unrelated matter. During
the trial, the government asked Petrow if he remem-
bered Lowe’s arrest in February of 1996, referring to the
arrest in Rockford. Petrow responded that Lowe “was
arrested in Kentucky a while back.” Although the district
Nos. 00-4184 & 00-4214                                     19

court immediately ordered that this statement be strick-
en from the record, Lowe moved for a mistrial. The dis-
trict court denied the motion, but admonished the jury
to disregard the testimony and to refrain from specula-
tion on its meaning since it had no relevance to the cur-
rent charges. We review the denial of a motion for mistrial
for abuse of discretion. See United States v. Wilson, 237
F.3d 827, 836 (7th Cir. 2001).
  At the outset, we note that jurors are presumed to fol-
low limiting and curative instructions unless the matter
improperly before them is so powerfully incriminating
that they cannot reasonably be expected to put it out of
their minds. See Richardson v. Marsh, 481 U.S. 200, 207-08
(1987). In Richardson, the Court focused on the extent
to which the improper testimony criminally implicated
the defendant and the likelihood that the jury would dis-
regard the curative instruction. Id. Here, it is reasonable to
believe that the jury could place the Kentucky arrest out of
their minds, especially since it was unrelated to any of the
other testimony at trial and was unadorned with additional
details. This is not the type of striking testimony that
would be engraved in the mind of the jury. The testimony
is also insufficient to overcome the presumption that the
jurors obeyed their curative instructions. The district court
did not err in denying the motion for a mistrial.


  5. The special verdict for quantity of marijuana.
  Lowe claims the district court abused its discretion
when it asked the jury to determine the amount of mari-
juana by range rather than specifying an exact amount.
Decisions by the district court regarding jury instruc-
tions are reviewed for an abuse of discretion. United
States v. Reed, 227 F.3d 763, 770-71 (7th Cir. 2000). How-
ever, when the instructions are based on an error of law, we
review de novo. Savino v. C.P. Hall Co., 199 F.3d 925, 934
20                                  Nos. 00-4184 & 00-4214

(7th Cir. 1999) (stating that jury instructions are reviewed
de novo “to determine whether they provide fair and accu-
rate summaries of the law”).
  Here, the district court, at the request of the govern-
ment, provided jury instructions and verdict forms that
required the jury to make special findings regarding the
quantity of marijuana involved in the conspiracy count.
This procedure is a byproduct of United States v. Apprendi,
530 U.S. 466 (2000), which held that “any fact (other
than prior conviction) that increases the maximum pen-
alty for a crime must be proven beyond a reasonable
doubt.” Id. at 476. Because § 841(b) specifies four ranges
of drug amounts that carry four different statutory maxi-
mum sentences, see note 4, supra, this court has man-
dated that “the trier of fact must be instructed to find,
both the elements of the offense, as listed in § 841(a), and
the drug amounts listed in § 841(b) that the prosecutor
relies on to establish the maximum [statutory] penalty.”
United States v. Trennell, 290 F.3d 881, 887 (7th Cir. 2002);
see also United States v. Rodgers, 245 F.3d 961, 965 (7th
Cir. 2001) (“In the wake of Apprendi, it is clear that any
finding as to a drug quantity that has the effect of in-
creasing the statutory maximum prison term must be
charged and submitted to the jury.”).
  While we believe that the district court’s jury instruc-
tions complied with the requirements of Apprendi, the
critique presented here is slightly different. Lowe claims
that the quantity of drugs involved, under § 841(b)(1), is
an element of the offense, and as such, the jury must
unanimously agree on the precise amount of the drugs
at issue. Lowe claims that the district court impermis-
sibly provided in its instructions four ranges of drug
amounts, which correspond to the four subsections of
§ 841(b)(1). Lowe argues that the district court erred
when it rejected his special verdict form requiring the jury
Nos. 00-4184 & 00-4214                                      21

to agree on the specific amount of marijuana Lowe con-
spired to possess. According to Lowe, the jury could
have been divided over the occurrence of particular trans-
actions involving different quantities of drugs. The jury
instructions regarding range rather than specific drug
amounts could have therefore resulted in a compromise
verdict, with the jury divided over which transactions
formed the basis of the conviction.
  Although Lowe does not frame his argument in this
way, he is essentially trying to advance two related, but
ultimately discrete, legal theses: (1) that drug quantity
is an element of a § 841 offense, and (2) that the jury
must unanimously agree on the precise amount of drugs,
rather than a range.
  In this circuit, the answer to the first question is clear.
Drug quantity is not an element of a § 841 drug offense.
See, e.g., United States v. Trennell, 290 F.3d 881, 887 (7th
Cir. 2002) (stating that “drug quantity is not an element
of the offense under § 841”); United States v. Bjorkman,
270 F.3d 482, 490-91 (7th Cir. 2001) (same); United States
v. Brough, 243 F.3d 1078, 1080 (7th Cir. 2001) (same). An
“element” of a criminal offense is ultimately a fact that
must be charged in an indictment and proven beyond
a reasonable doubt to support a conviction. See Bjorkman,
270 F.3d at 492; see also Richardson v. United States,
526 U.S. 813, 817 (1999) (“Calling a particular kind of fact
an ‘element’ carries certain legal consequences. . . . [A] jury
in a federal criminal case cannot convict unless it unani-
mously finds that the Government has proved each ele-
ment.”) (citation omitted). However, in the instance of
§ 841, if the jury instructions do not adequately address the
amount of drugs the defendant conspired to possess with
the intent to distribute, Apprendi limits the sentencing
court to a period of incarceration at or below the default
statutory maximum. See United States v. Mietus, 237 F.3d
22                                 Nos. 00-4184 & 00-4214

866, 874 (7th Cir. 2001) (holding that Apprendi limited
sentencing court to the default statutory maximum of
five years, 21 U.S.C. § 841(b)(1)(D), when jury was in-
structed only to find whether the defendant possessed
and conspired to possess a “measurable amount” of mari-
juana); United States v. Westmoreland, 240 F.3d 618, 632
(7th Cir. 2001) (same). If drug amount were a true ele-
ment of § 841, then a failure by the jury to agree on the
drug amount would mean that “there is no offense at all.”
Bjorkman, 270 F.3d at 492 (emphasis in original).
  Lowe’s second argument regarding range is integrally
tied in with the requirements of Apprendi. In the present
case, the indictment specified an amount of marijuana
in the vicinity of 1200 kilograms. In addition, the special
verdict revealed that the jury unanimously agreed that
Lowe “conspired to possess with the intent to distribute
more than 50 kilograms of marijuana, but less than 100
kilograms of marijuana.” The statutory maximum sen-
tence for this quantity of drugs is 20 years. See 18 U.S.C.
§ 841(b)(1)(C). We do not believe that, under Apprendi, the
district court was required to take the additional step of
asking the jury to return a specific finding of drug amount,
which would ostensibly reflect the jury’s agreement on
the occurrence of specific drug transactions.
  In this context, we believe that a precise drug amount
in relation to a statutory range is analogous to the cir-
cumstance in which the jury unanimously agrees on the
presence of a particular element but disagrees as to the
method or means by which it arose. For example, in
Richardson, the Court observed that “a federal jury need
not always decide unanimously which of several possible
sets of underlying brute facts make up a particular ele-
ment.” 526 U.S. at 817. The Court then provided the
following lucid example:
     Where, for example, an element of robbery is force or
     the threat of force, some jurors might conclude that
Nos. 00-4184 & 00-4214                                   23

      the defendant used a knife to create the threat of
      force; others might conclude that he used a gun. But
      that disagreement—a disagreement about means—
      would not matter as long as all 12 jurors unanimously
      concluded that the Government had proved the nec-
      essary related element, namely, that the defendant
      had threatened force.
Id.
   If a simple robbery conviction can brook a modicum of
disagreement as to means or method by which force
was applied or threatened, so too can a conviction on a
federal drug conspiracy that involved two defendants
and numerous alleged transactions over a period of
four years allow for some disagreement over the par-
ticular transactions that the conspiracy encompassed.
Further, a ruling to the contrary would inevitably ham-
string the government in its ability to effectively pros-
ecute more complex drug conspiracies in which the al-
leged wrongdoings span decades and include thousands
of discrete drug transactions. See, e.g., United States
v. Patterson, 215 F.3d 776, 778 (7th Cir. 2000) (fifteen
defendants in a decade-long conspiracy that grossed
$40,000 a day), vacated in part, 531 U.S. 1033 (2000);
United States v. Boyd, 208 F.3d 638, 640-41 (7th Cir. 2000)
(five defendants in a “continuing and wide-ranging [nar-
cotics] conspiracy reaching back to the mid-1960s”),
vacated, 531 U.S. 1135 (2001).
  In any event, Lowe’s logic is fundamentally flawed
in advancing the proposition that jury agreement on a
specific amount of drugs would necessarily guarantee
jury agreement about the particular transactions encom-
passed by the conspiracy. Juror A might be convinced of
the occurrence of Transaction M, involving 2 kilos, Trans-
action N, involving 3 kilos and Transaction O, involving
4 kilos, for a total of 9 kilos. Juror B, on the other hand,
24                                 Nos. 00-4184 & 00-4214

might have in mind Transaction P, involving 5 kilos
and Transaction O, involving 4 kilos, again for a total of
9 kilos. That in each case the specific amount of drugs
totaled 9 kilos would not assure jury unanimity on the
specific transactions supporting the conviction. For all the
reasons stated above, we hold that the district court’s
special verdict form, reflecting ranges of drug amounts
under § 841(b)(1), was in accordance with law and not
an abuse of discretion.


6. Limits on Smith’s cross examination of Lowe’s defense
   witnesses.
  Smith alleges that the district court improperly pre-
cluded him from cross-examining any of Lowe’s wit-
nesses, including Lowe, who presented testimony poten-
tially adverse to Smith. As we noted earlier in connec-
tion with the limitations of Lowe’s cross examination of
Swick, a district court’s evidentiary rulings are reviewed
for abuse of discretion, Aldaco, 201 F.3d at 985, but
the standard of review becomes de novo when an ad-
verse evidentiary ruling implicates the defendant’s Sixth
Amendment right to confront witnesses, Cavender, 228
F.3d at 798.
  Although resolution of this issue is quite straightfor-
ward, the following context is necessary to an understand-
ing of Smith’s meritless claim. Because this case in-
volved a joint trial of Lowe and Smith, Lowe presented
his defense before Smith. Before Lowe began his defense,
the government inquired about the order of cross exam-
ination as between itself and Smith. The district court
stated, “Well, [counsel for Smith] may cross as to any-
thing related to his client, but otherwise he really is
going to have to call him. . . . I think it’s better to do it
that way. Then the jurors will have it straight who is
Nos. 00-4184 & 00-4214                                  25

being called by whom.” During this exchange, Smith’s law-
yer commented, “I understand, Judge. That’s fine.”
  The next day, counsel for Lowe presented impeach-
ment evidence that suggested Swick might have ob-
served large quantities of marijuana at Smith’s body
shop. Counsel for Smith requested a limiting instruc-
tion because the impeachment evidence should not be
admitted against Smith on the conspiracy charges. The
district court replied, “I understand that. The reason I
limited you before is because I think you wanted to get
out evidence that you thought might be helpful to your
client, and I thought it was better to separate it from
the other defendants. But if there’s something that comes
out that you think is adverse, I’ll let you cross-examine.”
During the same exchange, Smith’s counsel acknowl-
edged that the inconsistency of statements made by
Lowe’s first two witnesses had been of minor importance
and could be effectively addressed during his own direct
examination. Smith’s counsel then expressed concern
about Lowe’s subsequent witnesses, including Lowe him-
self. Yet, Smith’s counsel did not request an opportunity
to cross-examine either Lowe or his two remaining charac-
ter witnesses.
  Thus, as is apparent from the record, the major prob-
lem with Smith’s argument is that counsel for Smith
explicitly agreed to the court’s handling of some of the
witnesses and failed to assert his right to cross-examine
others, despite the court’s ruling that he “[might] cross
as to anything related to his client.” Cast in the light
most favorable to Smith, any claim that the prescribed
cross examination procedure infringed upon Smith’s
Sixth Amendment rights has either been waived or for-
feited or some combination of the two. See Penny, 60 F.3d
at 1261 (stating that constitutional prohibition against
double jeopardy is waived “when there is the ‘intentional
relinquishment or abandonment of a known right’ ” and
26                                  Nos. 00-4184 & 00-4214

that “the simple failure to assert a right–forfeiture–
is distinct from an intentional act–waiver”) (quoting
United States v. Olano, 507 U.S. 725, 733 (1993)).
   Waiver of a personally-held constitutional right “is not
reviewable,” whereas forfeiture of that same right may
be reviewed for plain error. Penny, 60 F.3d at 1261. In
that respect, “[o]nly those errors that affect substantial
rights and ‘seriously affect the fairness, integrity, or pub-
lic reputation of judicial proceedings’ . . . amount to plain
error warranting reversal.” United States v. Haywood, 70
F.3d 507, 511 (7th Cir. 1995) (quoting Olano, 507 U.S. at
732). Smith fails to point to a single example of how his
substantial rights were harmed by the cross examination
procedure prescribed by the court. Based on our review of
the record, the district court’s handling of witnesses ap-
pears to have been quite sensitive to Smith’s procedural and
substantive rights. The district court did not err in this
issue.


                             B.
  Lowe raises three issues on appeal as to sentencing, and
Smith raises one. Both defendants challenge the method
of the district court’s fact-finding at sentencing. Lowe fur-
ther alleges that the district court erred in finding
the presence of a firearm, which raised his offense level. Fi-
nally, Lowe argues that the district court erred in deter-
mining his criminal history.


  1. Preponderance of the evidence standard at sentencing.
  Lowe alleges that the trial court improperly applied
the preponderance of evidence standard when determin-
ing the applicable amount of drugs under the Sentenc-
ing Guidelines. Lowe argues that a more demanding evi-
dentiary standard was warranted because the district
Nos. 00-4184 & 00-4214                                  27

court’s relevant conduct determination drastically in-
creased his sentence beyond what he would have re-
ceived if his sentence had been calculated using the
smaller quantity of drugs found by the jury. Further,
Lowe claims that Apprendi limits the trial court to find-
ing the amount of drugs specified by the jury in the
special verdict. When reviewing sentencing determina-
tions under the Guidelines, we review the district court’s
legal conclusions de novo and its findings of fact for
clear error. United States v. Parolin, 239 F.3d 922, 927-28
(7th Cir. 2000).
  At the outset, we note that Lowe conflates the jury’s
factfinding role during trial with the district court’s
factfinding role during sentencing. To put it simply, the
two fact finders make separate findings of fact for two
distinct purposes. The adjudication of guilt is concluded
once the jury finds the defendant guilty beyond a rea-
sonable doubt. Then, during the sentencing phase, the
judge assesses the facts under the relevant provisions of
the Sentencing Guidelines and employs a preponderance
of the evidence standard. United States v. Zehm, 217 F.3d
506, 511 (7th Cir. 2000); Talbott v. Indiana, 226 F.3d
866, 869 (7th Cir. 2000); U.S.S.G. § 6A1.3, cmt. (discuss-
ing preponderance of the evidence as the recommended
standard). Here, Lowe claims that there were special
circumstances that required the district court to depart
from this usual framework. First, Lowe argues that a
more exacting standard than preponderance must be ap-
plied when the court’s factual findings as to drug
amount markedly exceed the findings of the jury, thereby
producing a much more severe sentence under the Sen-
tencing Guidelines. Second, Lowe contends that Apprendi
effectively caps the district court’s findings as to the
drug amount at the level determined by the jury.
  Here, the jury found, by special verdict, that Lowe
conspired to possess and distribute 50 to 100 kilograms
28                                     Nos. 00-4184 & 00-4214

of marijuana. Under U.S.S.G. § 2D1.1, this amount
would produce a base offense level of 24.5 Under a pre-
ponderance of the evidence standard, the district court
found that Lowe conspired to possess and distribute
528 kilograms of marijuana, setting the base offense level
at 28. U.S.S.G. § 2D1.1(6). Both of these base offense
levels would then be increased by adding 8 points relat-
ing to several adjustments, including presence of a fire-
arm, obstruction of justice and Lowe’s leadership role.6
The smaller quantity of drugs (the jury determination)
therefore results in a 32 offense level, which in turn pro-
duces a sentencing range of 151 to 188 months, given
Lowe’s Category III criminal history.7 However, the dis-
trict court relied on the larger drug amount to reach a
36 offense level, which produced a sentence of 240 months.
  Lowe claims that the district court must apply a clear
and convincing standard of proof when its findings of
fact lead to a disproportionately large increase in a de-
fendant’s sentence (in this case, 52 months). To support
his argument, Lowe directs our attention to United States
v. Rodriguez, 67 F.3d 1312 (7th Cir. 1995), where we
stated in dicta that a case might require a higher stan-
dard of proof when the finding at sentencing becomes


5
   The categories under 21 U.S.C. § 841(b)(1) and U.S.S.G. § 2D1.1
do not directly coincide. A finding of 50-100 kg. of marijuana fits
§ 841(b)(1)(C) precisely, but spans three separate U.S.S.G. ranges:
§ 2D1.1(1) (40-60 kilograms); § 2D1.1(9) (60-80 kilograms) and
§ 2D1.1(8) (80-100 kilograms), resulting in a base offense level
of 24. The district court acknowledged it would use the 80-100
kilogram category if it were to adopt the jury’s finding.
6
  The preponderance of the evidence standard is not an issue
for these offense level adjustments. Lowe does challenge the fire-
arm finding on different grounds. This issue is addressed below.
7
  Lowe challenges his criminal history, which is also addressed
as a separate issue below.
Nos. 00-4184 & 00-4214                                       29

“ ‘the tail that wags the dog of the substantive offense.’ ” Id.
at 1322 (quoting McMillan v. Pennsylvania, 477 U.S. 79,
84 (1986); see also United States v. Hardin, 209 F.3d 652,
654 (7th Cir. 2000) (stating in dicta that “perhaps in
extreme circumstances . . . clear and convincing evidence
would be the standard of proof for sentencing factors”),
vacated, Sallis v. United States, 531 U.S. 1135 (2001).
However, in the seven years since we decided Rodriguez,
we have yet to find a sentencing disparity that warrants
this heightened evidentiary standard. And certainly,
there is nothing about Lowe’s sentence that would cause
us to break new ground today. See, e.g., Rodriguez, 67
F.3d at 1322-23 (finding preponderance of evidence ap-
propriate for relevant conduct determination that ex-
tends sentence from 51-63 months to life in prison);
United States v. Masters, 978 F.2d 281, 283-85 (same for
sentence increase from 33-41 months to 40 years). Thus,
although the principle of Rodriguez remains viable, it has
no application to the case before us.
  Lowe’s Apprendi argument is also meritless. Under
Apprendi, when a sentence was increased above the
statutory maximum, the facts underlying it had to be sub-
mitted to the jury and proven beyond a reasonable doubt.
530 U.S. at 490; United States v. Wallace, 276 F.3d 360,
369 (7th Cir. 2002) (“[T]o the extent that a drug quantity
affects a defendant’s statutory maximum sentence, it is an
aspect of the crime that . . . must be proven beyond a
reasonable doubt”) (emphasis added); Brough, 243 F.3d
at 1079-80 (same); United States v. Nance, 236 F.3d 820,
825 (7th Cir. 2000) (same). Here, through the use of the
special verdict form, the jury unanimously determined that
Lowe conspired to distribute 50-100 kilograms of mari-
juana. Under § 841(b)(1)(C), the statutory maximum for
that quantity of drugs is 20 years, which is the precise
sentence (240 months) imposed here by the district court.
Therefore, since the drug amount as determined by the
30                                     Nos. 00-4184 & 00-4214

district court did not push the sentence beyond the statu-
tory maximum, the district court correctly relied upon
a preponderance of the evidence standard when making
its sentencing determinations.


    2. Quantity of drugs attributed to Smith.
  Smith claims the district court’s drug quantity finding
at sentencing was clearly erroneous. A district court’s
finding as to drug quantity for sentencing purposes
is reviewed for clear error. See Westmoreland, 240 F.3d
at 629-30; United States v. Bacallo, 149 F.3d 717, 719 (7th
Cir. 1998).
  The thrust of Smith’s argument is both simple and
without merit. Smith asserts that the government put
on evidence suggesting that he conspired to distribute
several hundred kilograms of marijuana, yet the jury
convicted him of an amount less than 50 kilograms. Smith
maintains that this disparity between the amount al-
leged by the government and the amount found by the
jury was inescapably a product of the jury having sig-
nificantly discounting the credibility of Rivas, Petrow
and Swick, who testified against Smith at trial. Since
the district court’s finding of 100 kilograms of mari-
juana rejected the collective wisdom of the jury and its
implied credibility findings, Smith concludes that the dis-
trict court committed clear error.8


8
  As in the case of Lowe, the district court’s factual findings as
to drug amount resulted in a sentence that was at the statutory
maximum for a violation of 21 U.S.C. § 841(b)(1)(D) (specifying
a maximum sentence of five years for engaging in a conspiracy
to distribute 50 kilograms or less of marijuana). This provision
corresponds, in terms of drug quantity, to the jury’s findings on
                                                    (continued...)
Nos. 00-4184 & 00-4214                                   31

  However, as noted earlier, the district court’s rele-
vant conduct findings for sentencing purposes, includ-
ing drug quantities, are governed by a less demanding
evidentiary standard than are determinations by the jury.
This is a fact of federal criminal procedure that Smith
(unlike Lowe) does not contest. Nonetheless, he con-
tends that even under this more lenient standard, the
testimony of the government’s three witnesses simply
cannot support a drug quantity finding larger than 50
kilograms because this is what the jury found. But cred-
ibility determinations by the district court using the
preponderance standard cannot be challenged on ap-
peal unless the court credited testimony that was essen-
tially unbelievable as a matter of law. See United States
v. Ray, 238 F.3d 828, 834 (7th Cir. 2001). We give excep-
tional deference to district courts on issues of credibility
in sentencing. See Amadeo v. Zant, 486 U.S. 214, 227
(1988); accord United States v. Johnson, 227 F.3d 807, 813
(7th Cir. 2000).
  Smith fails to identify any factor in the record that
would render the testimony of the government witnesses
essentially unbelievable. While he does point out that
some of this testimony was internally conflicting, the
mere presence of such conflicts does not in itself amount
to essential unbelievability nor support a finding of clear
error. Deference to the finder of fact, with the opportu-
nity to observe the witnesses, supports credibility find-
ings even in the face of some internal conflicts. Thus, ap-
plying the preponderance standard, the findings of the
district court, on which the sentence is based, are not
clearly erroneous.



8
  (...continued)
the special verdict form.
32                                 Nos. 00-4184 & 00-4214

  3. Presence of a firearm in connection with the offense.
  Lowe argues that the district court erred when it im-
posed a 2-level enhancement for possession of a firearm
in connection with the crime of conviction. See U.S.S.G.
§ 2D.1(b)(1). The possession of a firearm for sentencing
purposes is a question of fact reviewed for clear error.
See Nance, 236 F.3d at 826; United States v. Berthimaume,
233 F.3d 1000, 1002 (7th Cir. 2000). Further, one of the
application notes to § 2D1.1 states that an enhancement
for a firearm “should be applied if the weapon was present,
unless it is clearly improbable that the weapon was con-
nected with the offense.” § 2D1.1, cmt. n.3 (emphasis added)
(giving example of a hunting rifle as an unrelated firearm).
Once the government proves that a gun was present
in the commission of an offense, the burden shifts to the
defendant to show that it was clearly improbable that the
gun was connected with the offense. See Berthimaume, 233
F.3d at 1004.
   Here, a judge could reasonably conclude that several
of the firearms confiscated by police were connected with
the drug conspiracy. Police found several firearms at
Lowe’s residence, where he kept more than $100,000,
which was likely the product of the illegal drug trade.
When police executed the search warrant for Lowe’s used
car lot, which was used as the drop-off location for a van
filled with approximately 115 pounds of marijuana, they
found a loaded shotgun in the bathroom of the garage.
Lowe testified at trial that the shotgun belonged to his
mechanic and that he was unaware it was on the premises.
However, this assertion does not demonstrate a sufficient
improbability that the gun was connected to drug traf-
ficking. In any event, Lowe’s testimony does not establish
an innocent explanation for the presence of the guns
found at his residence, where he kept more than $100,000
in cash, presumably derived, at least in part, from drug
Nos. 00-4184 & 00-4214                                    33

trafficking. The district court’s ruling on the § 2D1.1(b)(1)
enhancement was not clearly erroneous.


  4. Lowe’s criminal history points.
  The final issue in this appeal is whether the district
court correctly calculated Lowe’s criminal history points.
Lowe insists that, under the Sentencing Guidelines, the
district court erroneously included two sentences of court
supervision, one following a guilty plea and the other
following a stipulation of facts. In the sentencing context,
we review the district court’s legal conclusions de novo
and its findings of fact for clear error. See Parolin, 239
F.3d at 927-28.
  Lowe had two prior Illinois offenses that resulted in
sentences of supervision for one year or more. One of
the sentences, eighteen months of supervision for unlawful
use of a firearm and possession of cannabis, was the
product of a guilty plea. The other sentence was one
year for disorderly conduct, to which Lowe had made a
stipulation of fact. Both orders of supervision provided
that upon successful completion of supervision without
further offense, the charges would be dismissed. When cal-
culating criminal history points under the Guide-
lines, the district court must consider prior offenses that
have led to a sentence of one year or more upon adjudica-
tion of guilt. U.S.S.G. § 4A1.2(a). The district court as-
signed four points for the firearm/cannabis sentence and
one point for the disorderly conduct sentence, placing
Lowe in a Category III criminal history. Lowe contends
that because he pleaded guilty or stipulated to the facts,
and because the sentences were for “supervision,” they
did not result from an adjudication of guilt, nor should
they qualify as “prior history.”
34                                 Nos. 00-4184 & 00-4214

  Under the Sentencing Guidelines, a “prior sentence” is
included in a criminal history only if it was “imposed upon
adjudication of guilt.” U.S.S.G. § 4A1.2(a). The definition
of a “prior sentence” includes sentences of probation and
sentences that were totally suspended or stayed, all of
which must be counted as part of a defendant’s prior
criminal history. U.S.S.G. § 4A1.2(a)(3); see also United
States v. Burke, 148 F.3d 832, 839 (7th Cir. 1998) (treat-
ing supervision under Illinois law as the equivalent of
probation and counting one year of supervision as part of
criminal history even though the charges were eventual-
ly dismissed); United States v. Binford, 108 F.3d 723, 727
(7th Cir. 1997) (ruling that Illinois sentence of one-year
court supervision is properly a prior sentence for Guide-
line purposes). It is immaterial that the sentence re-
sults from a guilty plea or from a stipulation of facts
because both count for criminal history purposes. See
United States v. Smith, 223 F.3d 554, 578-79 (7th Cir.
2000) (holding that the practical effects of stipulation are
similar enough to those resulting from a plea of nolo
contendere to qualify as prior history for sentencing pur-
poses).
   Here, there was no error. The points assigned to the
firearm/cannabis sentence were appropriate because a
guilty plea is an adjudication of guilt under Illinois law.
Moreover, the supervisory sentence was equivalent to
more than one year of probation, and the eventual dismiss-
al of the charge is immaterial for sentencing purposes.
The four points attributable to the firearm/cannabis sen-
tence are sufficient to place Lowe in Category III;
hence, any error in attributing one pont to the disorderly
conduct sentence is harmless. Even so, the disorderly
conduct offense also appears to satisfy the requirements
of § 4A1.2(a). It was therefore appropriate to include
both sentences as part of the criminal history calculation.
Nos. 00-4184 & 00-4214                                     35

                             III.
  In summary, all the issues pertaining to the trial of
Danny Smith and Harry Lowe are unavailing. The dis-
trict court did not abuse its discretion when it (1) denied
Lowe’s Rule 14 motion to sever, (2) denied his motion for
a new trial based on alleged defects in the chain of evi-
dence and (3) denied his motion for a new trial based on
Petrow’s mention of a prior arrest in Kentucky. Under a
more stringent de novo standard of review, the district
court also did not err when it (4) prohibited Lowe’s attor-
ney from cross-examining Swick with agent White’s af-
fidavit, (5) narrowed the scope of Smith’s cross exam-
ination of Lowe’s defense witnesses and (6) gave jury
instructions that permitted jurors to agree on a range of
drug amounts that corresponded to the various drug
amount ranges in § 841(b)(1) rather than a precise drug
amount.
  All the sentencing issues raised by the defendants al-
so fail. The district court did not commit clear error when it
(1) found that Smith conspired to distribute 100 kilograms
of marijuana and (2) imposed a 2-level enhancement to
Lowe’s base offense level for possession of a firearm related
to the charge of conviction. The district court also did not
err when it (3) applied the preponderance of evidence
standard to determine the amount of marijuana Lowe
conspired to distribute and (4) calculated Lowe’s criminal
history points.
  For the foregoing reasons, the judgment of the district
court is AFFIRMED.
36                              Nos. 00-4184 & 00-4214

A true Copy:
      Teste:

                    ________________________________
                    Clerk of the United States Court of
                      Appeals for the Seventh Circuit




               USCA-02-C-0072—10-16-02
