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

No. 05-4678
UNITED STATES OF AMERICA,
                                                 Plaintiff-Appellee,
                                v.

CRISS E. DUNCAN,
                                             Defendant-Appellant.
                         ____________
            Appeal from the United States District Court
     for the Northern District of Indiana, South Bend Division.
                No. 03 CR 57—Allen Sharp, Judge.
                         ____________
    SUBMITTED APRIL 20, 2006—DECIDED MARCH 22, 2007
                         ____________


 Before BAUER, POSNER and RIPPLE, Circuit Judges.
  PER CURIAM. In this successive appeal, Criss E. Duncan
challenges the reasonableness of his sentence of 457
months’ imprisonment on the ground that application of
18 U.S.C. § 924(c)(1)(B)(ii)’s mandatory minimum sen-
tence of 360 months’ imprisonment resulted in an unwar-
ranted disparity between his sentence and the sentence
received by his codefendant, Ralph Berkey, Jr. For the
reasons set forth in this opinion, we conclude that the
sentence imposed is reasonable under 18 U.S.C. § 3553(a)
and affirm the decision of the district court.
2                                               No. 05-4678

                             I
                     BACKGROUND
                             A.
  On May 27, 2003, Duncan and Berkey robbed the Na-
tional City Bank in Leesburg, Indiana. In the course of the
robbery, the two men wore camouflage fatigues, masks and
body armor and carried assault-style rifles, which had
been modified from semi-automatic to fully automatic by
Berkey and another man. They fled the scene in a van
with $43,000. Following their escape, Duncan and Berkey,
still carrying their weapons, set fire to the van and changed
vehicles to a pickup truck. When the two men encountered
David Hobbs, the Milford, Indiana Chief of Police, at a
roadblock, Berkey opened fire upon Hobbs. Duncan and
Berkey then fled to Cassopolis, Michigan, where they
hid in a wooded area, planning to resist violently any
attempt to apprehend them. The authorities did not arrive.
Duncan and Berkey then left the area, but subsequently
returned to retrieve the money and weapons they had
left in the pickup.
  Authorities eventually linked Duncan and Berkey to the
robbery and assault upon Chief Hobbs and arrested the
two men on May 31, 2003. Both were indicted in the
Northern District of Indiana on a two count indictment
charging bank robbery in violation of 18 U.S.C. § 2113(a)
and (d) and using a firearm during and in relation to a
crime of violence in violation of 18 U.S.C. § 924(c)(1)(A).
Both men subsequently were charged with the attempted
manslaughter of Chief Hobbs in state court.
No. 05-4678                                               3

                            B.
  Berkey entered into a plea agreement with federal
prosecutors. Under the agreement, he would plead guilty
to both counts in his federal indictment, as well as to a
separate charge of aiding and abetting in the malicious
damage by fire to a vehicle in violation of 18 U.S.C. §§ 2
and 841(i) for burning the getaway van. He also agreed to
plead guilty to the state charge of attempted manslaughter.
The plea agreement was conditioned on Berkey receiving
a sentence of no less than 20 years’ imprisonment for his
state conviction of attempted manslaughter. In exchange,
the Government promised to recommend the minimum
sentence under the Sentencing Guidelines, including the
maximum credit for acceptance of responsibility in cal-
culating Berkey’s total offense level.
  Berkey was sentenced to 20 years’ imprisonment in
Indiana state court for his conviction of attempted man-
slaughter. At sentencing on the federal charges, after
granting a three-level reduction for acceptance of responsi-
bility, the district court calculated Berkey’s offense level
for the counts of bank robbery and burning the getaway
van under the Guidelines to be 20 and his criminal history
category of III. The resulting sentencing range was 41-51
months’ imprisonment. The district court further found
that the use of a firearm in connection with a crime of
violence carried a mandatory minimum sentence of 120
months’ imprisonment to be served consecutively to
Berkey’s sentence for bank robbery and burning the
getaway van. See 18 U.S.C. § 924(c)(1). The district court
decided to sentence Berkey to 41 months’ imprisonment
for the bank robbery and burning the getaway van, result-
ing in a total sentence of 161 months’ imprisonment for
his federal offenses. Berkey’s federal sentence was to be
4                                              No. 05-4678

served consecutive to his state sentence, resulting in a
combined sentence of 401 months’ imprisonment.


                            C.
   Duncan chose to go to trial on both his state and federal
charges. The federal prosecutor, in turn, filed a super-
ceding indictment against Duncan, adding four counts. The
first two additional counts related to a separate bank
robbery. The superceding indictment also charged Duncan
with aiding and abetting the malicious damage by fire to
a vehicle in violation of 18 U.S.C. §§ 2 and 844(i) for
burning the getaway van and for being a felon in posses-
sion of a firearm in violation of 18 U.S.C. §§ 922(g)(1) and
924(a) based on seven other weapons found in Duncan’s
home. Duncan was acquitted of the attempted manslaugh-
ter charge in state court. In federal court, the jury was
unable to reach a verdict on the two counts related to an
earlier bank robbery, but returned a guilty verdict on the
remaining counts.
  The district court calculated Duncan’s sentence under the
Guidelines. First, the district court grouped Duncan’s
convictions of bank robbery and burning the getaway
van for purposes of calculating the applicable offense
level, just as it had when calculating Berkey’s sentence.
However, the district court concluded that the applicable
offense level for these two offenses in Duncan’s case was
26, as opposed to 20. The difference in offense levels
resulted from the district court imposing a three-level
enhancement to Duncan’s base offense level because, based
on Berkey’s firing upon Chief Hobbs, the offense in-
volved an official victim. The district court had not im-
posed the enhancement when calculating Berkey’s offense
No. 05-4678                                                5

level out of concern that, because Berkey had been sen-
tenced in state court for this conduct in connection with his
attempted manslaughter conviction, such an enhancement
would violate the Fifth Amendment’s Double Jeopardy
Clause. Additionally, Berkey had received a three-level
reduction in his offense level for acceptance of responsi-
bility and assisting the Government in its prosecution of
Duncan. The district court then increased Duncan’s offense
level by two levels as a result of his separate, non-grouped
conviction for felon in possession of a firearm. This re-
sulted in a total offense level of 28, which, with Duncan’s
criminal history category of III, resulted in a sentenc-
ing range of 97-121 months’ imprisonment.
  As with Berkey, the district court concluded that 18
U.S.C. § 924(c)(1) imposed a mandatory minimum sen-
tence for possession of a firearm in connection with a
crime of violence and that such sentence was to run
consecutive to Duncan’s other sentence. However, because
the district court found that the firearm used by Duncan
was a machine gun, the mandatory minimum for Duncan’s
conviction was 360 months’ imprisonment. See 18 U.S.C.
§ 924(c)(1)(B)(ii). The district court had made no similar
finding with respect to Berkey. The district court then
sentenced Duncan to 97 months’ imprisonment for his
convictions for bank robbery, burning the getaway van
and felon in possession of a firearm, the bottom of the
Guidelines range, to run consecutive to the statutory
mandatory minimum for Duncan’s conviction for posses-
sion of a firearm in connection with a crime of violence.
This calculation brought Duncan’s total sentence to 457
months’ imprisonment.
6                                              No. 05-4678

                            D.
  Duncan appealed his sentence, arguing that he was not
subject to the 360 month mandatory minimum sentence
because the fact that the firearm used in connection with
the bank robbery was a machine gun was neither admitted
nor found by a jury beyond a reasonable doubt. We
rejected this argument, noting that United States v. Booker,
543 U.S. 220 (2005), had no effect on the Supreme Court’s
decision in Harris v. United States, 536 U.S. 545 (2002),
which upheld the imposition of a statutory mandatory
minimum sentence based on facts found by a judge. See
United States v. Duncan, 413 F.3d 680, 683 (7th Cir. 2005).
However, because the district court had sentenced Duncan
prior to Booker, we ordered a limited remand under
United States v. Paladino, 401 F.3d 471 (7th Cir. 2005), to
determine whether it would have imposed the same
sentence under the now-advisory Guidelines. Duncan, 413
F.3d at 684.
  On remand, the district court re-sentenced Duncan to
serve his sentences for bank robbery, burning the get-
away van and felon in possession of a firearm concur-
rently with his sentence for using a firearm during and
in relation to a crime of violence. The Government ap-
pealed, and we reversed the decision of the district court,
holding that the district court did not have jurisdiction
to re-sentence under our limited remand. See United States
v. Duncan, 427 F.3d 464, 465 (7th Cir. 2005). Following this
second remand, the district court affirmed its initial
sentence of 457 months’ imprisonment. The district court
noted that it had considered the sentence in light of both
the facts of the case and the factors listed in 18 U.S.C.
§ 3553(a), and found that a sentence of 457 months’ impris-
onment was appropriate under the circumstances.
No. 05-4678                                                7

  The court noted that the 360 month mandatory minimum
for use of a fully automatic machine gun in the course of a
violent felony reflected the judgment of Congress that use
of such weapons in the course of a violent felony was
deserving of a minimum sentence of thirty years’ imprison-
ment. The court held that this minimum sentence ac-
counted only for the means by which the defendant
committed a violent felony, not the characteristics of the
violent felony itself. The court found that a sentence of 457
months’ imprisonment reflected the seriousness of the
manner in which the felony was perpetrated and better
satisfied the § 3553(a) factors.


                             II
                      DISCUSSION
  Duncan does not challenge the accuracy of the guidelines
calculation that led to his sentence under the Advisory
Guidelines; he challenges only the sentence’s reasonable-
ness in light of the factors listed in 18 U.S.C. § 3553(a).
Duncan bases this assertion solely on the ground that
the difference between the sentence the district court
imposed on him compared to the sentence imposed on
Berkey amounted to an unwarranted disparity under
§ 3553(a)(6). Duncan bases this contention on the differ-
ence between the district court’s sentence of 457 months’
imprisonment for his convictions and Berkey’s federal
sentence of 161 months’ imprisonment arising out of the
same events.
  We first note that the difference between the sentences
received by Berkey and Duncan is not as great as Duncan
claims. Berkey received a total sentence of 401 months’
imprisonment and Duncan received a sentence of 457
8                                                 No. 05-4678

months’ imprisonment, a difference of 56 months. Al-
though 240 months of Berkey’s imprisonment will be
served on his state conviction for attempted manslaughter,
Berkey’s plea agreement in federal court was expressly
conditioned on a plea of guilty and sentence of not less
than 20 years for his state charge of attempted manslaugh-
ter.1 The Government’s decision to accept Berkey’s plea
under the terms of the plea agreement rather than pursue
the higher mandatory minimum under 18 U.S.C.
§ 924(c)(1)(B)(ii) applicable when the firearm used in
connection with a crime of violence is a machine gun that
was applied to Duncan is a matter of prosecutorial discre-
tion. Absent a showing of invidious discrimination, we
shall not second guess a prosecutor’s decision regarding
the charges it chooses to bring. See United States v. Roberson,
474 F.3d 432, 434 (7th Cir. 2007); see also United States v.
Armstrong, 517 U.S. 456, 464 (1996); United States v. Blake,
415 F.3d 625, 627 (7th Cir. 2005).
  The remaining difference between the two sentences
is attributable to the applicable sentencing range for each
man under the Advisory Guidelines. Both men had a
criminal history category of three. The sole difference in the
sentencing ranges was their respective total offense levels.
Duncan’s total offense level was 28, for which the applica-


1
  We recognize that Indiana’s rules for awarding good time
credit differ considerably from those that apply to federal
sentences. The award of good time credit in Indiana is contin-
gent and depends on satisfying the statutory requirements,
see Ind. Code § 35-50-6-3 & -4 (providing for the calculation of
good time credit), and may be revoked under a number of
circumstances, see id. § 35-50-6-5(a) (listing the conduct for
which an inmate may be deprived of good time credit).
No. 05-4678                                                  9

ble sentencing range was 97-121 months’ imprisonment,
and Berkey’s total offense level was 20, for which the
applicable sentencing range was 41-51 months’ imprison-
ment. Both Duncan and Berkey were sentenced at the
bottom of the applicable sentencing range, a difference
of exactly 56 months’ imprisonment. Duncan does not
challenge the correctness of either sentencing range under
the Advisory Guidelines.
  Sentencing differences attributable to properly calculated
sentencing ranges under the Advisory Guidelines cannot
be considered unwarranted disparities under 18 U.S.C.
§ 3553(a)(6). See United States v. Boscarino, 437 F.3d 634,
638 (7th Cir. 2006). 18 U.S.C. § 3553(a)(6) does not instruct
district courts to avoid all differences in sentencing,
only unwarranted disparities “among defendants with
similar records who have been found guilty of similar
conduct.” 18 U.S.C. § 3553(a)(6); see also Boscarino, 437 F.3d
at 638. “[A] sentencing difference is not a forbidden ‘dispar-
ity’ if it is justified by legitimate considerations, such as
rewards for cooperation,” id., or is the result of statutory
authorization, cf. United States v. Miller, 450 F.3d 270, 276
(7th Cir. 2006); United States v. Martinez-Martinez, 442
F.3d 539, 542 (7th Cir. 2006).
  Further, the differences between Duncan’s and Berkey’s
respective total offense levels demonstrate that the two
men were not similarly situated in terms of sentencing.
Part of the difference in the total offense levels flows from
Berkey’s three-level reduction for acceptance of responsi-
bility and cooperation with the Government in its prosecu-
tion of Duncan. Such assistance remains a legally appropri-
ate basis for differences in sentencing. Boscarino, 437 F.3d
at 638; see also United States v. Mendoza, 457 F.3d 726, 730-31
& n.6 (7th Cir. 2006) (noting that a defendant’s degree of
10                                              No. 05-4678

cooperation with the Government factors into the circum-
stances surrounding a crime). Closely related was the
district court’s decision to decline to apply a three-level
enhancement to Berkey’s offense level based on double
jeopardy concerns flowing from Berkey’s acceptance of
responsibility and sentencing in state court for the at-
tempted manslaughter of Chief Hobbs, a factor not relevant
to Duncan’s sentence. Lastly, Duncan received a two-
level enhancement to his offense level based on his con-
viction for a separate felon in possession charge, a charge
for which Berkey was not convicted.
  Even if we were to disregard Berkey’s state sentence, the
difference between Duncan’s and Berkey’s respective
sentences does not amount to an unwarranted disparity. As
noted above, 56 months of the difference was based on
differences in their offense levels under the Advisory
Guidelines. The remaining difference, 240 months’ impris-
onment, is attributable to the mandatory minimum sen-
tence under 18 U.S.C. § 924(c)(1) for use of a firearm during
and in relation to a crime of violence that applied to
each man. In the case of Duncan, the district court held
that, because the firearm used by Duncan was a machine
gun, the mandatory minimum sentence was 360 months’
imprisonment. For Berkey, the district court held that the
mandatory minimum was 120 months’ imprisonment.
However, as far as the record shows, the district court
had no information relating to the type of weapon used
other than the statement in Berkey’s petition to enter a
guilty plea, in which he characterized the weapon as a
semi-automatic. In that respect, Duncan and Berkey were
not found guilty of similar conduct. The Government’s
decision to forego the higher mandatory minimum applica-
ble when the firearm in question is a machine gun is a
No. 05-4678                                              11

matter of prosecutorial discretion. We shall not second
guess such an exercise of discretion absent a showing of
invidious motivation. See Roberson, 474 F.3d at 434.
   Further, the mandatory minimum to which Duncan
was subjected, by itself, would not justify a lower sentence
for Duncan’s other offenses. Courts may not apply
§ 3553(a) to reduce a statutory mandatory minimum
sentence. Id. at 436. That was the rule prior to Booker and
it remains so. Id. When a defendant is subject to a manda-
tory minimum under 18 U.S.C. § 924(c)(1), the district court
must calculate the sentence for the defendant’s other
offenses without regard to the mandatory minimum
sentence. See id. at 434. Although the sentence as a whole
must be reasonable, the district court may not reduce the
sentence for an underlying offense solely because the
defendant is subjected to a statutory add-on under 18
U.S.C. § 924(c)(1), as doing so effectively reduces the
mandatory minimum sentence. Id. at 436.
  Lastly, we must determine whether Duncan’s sentence
was reasonable in light of the factors listed in § 3553(a).
Prior to this conviction, Duncan had been convicted of
voluntary manslaughter and twice convicted of driving
while intoxicated. Duncan was a full participant in the
robbery of the National City Bank in Leesburg, Indiana:
Both he and Berkey entered the bank wearing camouflage
fatigues, body armor, helmets and masks and carrying
fully automatic weapons; Duncan helped to elude authori-
ties by burning the getaway van; Duncan drove the
vehicle from which Berkey opened fire on Chief Hobbs
and even handed Berkey his own weapon to assist Berkey;
and, following the shootout, both Duncan and Berkey
retreated to a wooded area and prepared to resist authori-
ties by force. This conduct was made all the more danger-
12                                              No. 05-4678

ous by Duncan’s use of a fully automatic machine gun. The
district court weighed all of these factors in addition to
the other factors listed in 18 U.S.C. § 3553(a) when arriv-
ing at Duncan’s sentence and determined that a sentence at
the bottom of the Advisory Guidelines range in addition
to the mandatory minimum sentence under 18 U.S.C.
§ 924(c)(1) reached the proper balance.
   A sentence within a properly-calculated Guidelines range
is entitled to a presumption of reasonableness. See United
States v. Mykytiuk, 415 F.3d 606, 608 (7th Cir. 2005). Even
if that were not the case, we find that Duncan’s sentence
was reasonable in light of 18 U.S.C. § 3553(a). Duncan’s
conduct in the course of the robbery of the National City
Bank and ensuing escape as well as his prior criminal
conduct demonstrate lack of respect for the rule of law
and that he posed a real and continuing danger to the
public safety. In light of the seriousness of Duncan’s
offense and his demonstrated threat to society, we cannot
say that this sentence, although substantial, was unrea-
sonable.


                        Conclusion
  The district court’s sentence of 457 months’ imprison-
ment is not unreasonable in light of the factors set forth
in 18 U.S.C. § 3553(a). The decision of the district court is
affirmed.
                                                  AFFIRMED
No. 05-4678                                           13

A true Copy:
       Teste:

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




                USCA-02-C-0072—3-22-07
