Donald Johnson and Robert Jones appeal from their 1988 convictions for armed bank robbery, in violation of 18 U.S.C. § 2113, and use of a firearm during a crime of violence, in violation of 18 U.S.C. § 924(c), in connection with the June 6, 1988, robbery of Anchor Bank in Myrtle Beach, South Carolina. Johnson and Jones assign numerous errors in the admission of evidence and denial of their motions. They further contend that the district court incorrectly applied the Federal Sentencing Guidelines, resulting in both defendants being sentenced as career offenders under § 4B1.1 of the Guidelines. We affirm the convictions but remand for resentencing under the interpretation of the Guidelines we outline below.
I
Johnson and Jones were convicted after a four-day trial in September 1988. At trial, the government presented the testimony of an FBI expert, who, evaluated bank surveillance photographs of the two *458robbers, both of whom had worn sunglasses and baseball caps, but no masks, during the robbery. The expert identified the defendants as the men in the photographs after comparing the bank photographs with others of the defendants. He also identified sunglasses and baseball caps seized from a residence leased by Johnson and his cousin as those worn by the robbers in the photographs. In addition, the government presented the testimony of five eyewitnesses — four bank tellers and a bank customer — who identified Johnson in court as one of the robbers; two bank tellers identified Jones in court as the other. These witnesses also testified to their identification of the defendants at an earlier line-up.
Other evidence showed that Jones and Johnson were together when they were arrested and that both had in their possession at that time a large quantity of five-dollar bills with sequential serial numbers. The government presented other circumstantial evidence, including testimony that the defendants were in the area of the bank at the time of the robbery, that they had had no cash immediately before the robbery, and that just before he was arrested, Johnson denied that he was Donald Johnson when asked.
The jury found both defendants guilty on both counts. Following recommendations in the presentencing reports, the court sentenced both Johnson and Jones as career offenders under § 4B1.1 of the Sentencing Guidelines. As a consequence of that most extreme of criminal history classifications, Johnson was sentenced to twenty-seven and a half years in prison, and Jones to twenty-seven years.
II
The first of the Johnson and Jones’ assignments of error focuses on an allegedly improper comment made by the court:
You will recall yesterday, I mentioned that there are a variety of reasons why a person accused of a crime may choose not to testify. And more often than not, that reason not to testify will have nothing to do with the merits of the case on trial.
Sometimes a defendant has a not too complimentary background and does not wish the United States Attorney to have the opportunity to bring these matters out before the jury.
And yet, such a person could be innocent of the offense being tried before you. So, that could be a reason a defendant might choose not to testify.
So once again, if one or both defendants were to choose not to testify, you should place no inference against them in that regard, since the constitution affords them the right not to testify.
I remind you that the defendants are presumed to be innocent. And the government must prove their guilt beyond a reasonable doubt.
The defendants do not have to prove their innocence.
Joint Appendix at 81 (emphasis added).
The appellants point to the underlined portion of this excerpt from the trial judge’s opening remarks and claim that this comment violated their fifth amendment right not to testify and to have no adverse inference suggested from the decision not to testify. They argue that the court’s comment violated the dictates of Griffin v. California, 380 U.S. 609, 85 S.Ct. 1229, 14 L.Ed.2d 106 (1965), which forbids negative commentary on a criminal defendant’s failure to testify.
Viewed in hindsight, the district judge’s effort to drive home the irrelevance of a defendant’s silence may have involved an improvident choice of example that was not worth the risk of misapprehension now seized upon by defendants. We do not condone it, precisely because of the obvious risk that in some contexts it could be prejudicial. But we are satisfied that, viewed realistically in total context of this case, it could not have been here. The remark was made as part of a strong admonition to the jury not to draw an unfavorable inference from silence, came before a four-day trial at which abundant evidence was presented, and was not repeated in the jury instructions, which included a cautionary state*459ment against adverse inference from silence. A jury would not “naturally or necessarily take [this] as a comment on the defendant’s refusal to testify,” see United States v. Lorick, 753 F.2d 1295, 1298 (4th Cir.1985), and any conceivable impropriety in the comment was surely cured by its immediate context and by a later cautionary instruction that omitted the allegedly offensive remark. See id.
Ill
The appellants next contend that their right to an impartial jury was violated when two jurors saw them in handcuffs. They concede that a taint of this sort can be corrected if the court takes the necessary steps, but argue that in this case the court’s general questions to each of the jurors were inadequate to ferret out bias.
Our review of the record indicates that the trial court was solicitous of the defendants’ wishes on how to question the jurors and that, in fact, defendants’ counsel had no objection at trial to the form of questioning. They now object to the generalized nature of the questions and to the fact that each juror was questioned. Ironically, both of these features were designed to protect the defendants: the general questions were meant to avoid any improper suggestion, and the blanket questioning was meant to test whether more than the two jurors might have heard about the handcuff scene.
Even assuming that these objections may now be heard, the questioning appears to have been thorough and careful. Each juror was asked whether he could reach a decision solely on the evidence and whether he had seen or heard anything out of court that might affect his decision. All answered no, and some were even probed further by the judge. In light of the trial court’s broad discretion in conducting voir dire and in formulating questions for jurors, United States v. Robinson, 804 F.2d 280 (4th Cir.1986); United States v. Griley, 814 F.2d 967 (4th Cir.1987), this form of questioning was not an abuse of discretion.
IV
Johnson and Jones next challenge the line-ups in which they were identified. They make two arguments: (1) that they were denied their sixth amendment rights to counsel because, although their lawyers were present at the line-ups, they were not allowed in the witness’ viewing room to monitor remarks of FBI agents conducting the line-up, and (2) the line-ups were overly suggestive because (a) other participants were joking with each other but not the defendants; (b) the others wore a variety of hats and sunglasses, but only the defendants wore ones like those used in the robbery; and (c) one of the defendants was required to repeat “Hit the floor!” — which the robbers had shouted — whereas the others said it only once. They contend further that the trial court erred in denying their motions to suppress both of these allegedly unconstitutional out-of-court identifications and tainted in-court identifications, which they claim had no independent basis.
We see no merit to the claimed violation of the right to counsel. Counsel was present in the line-up room with Johnson and Jones and had the opportunity to confer with them after the line-up. The appellants have cited no authority to the effect that counsel needs to be present in the witness room itself. There was testimony from one of the FBI agents that in his 22 years, lawyers had never been allowed in the viewing room. Furthermore, the defendants’ counsel had opportunities to cross-examine the witnesses who made the identifications and the FBI agents who conducted the line-up, and a picture of the line-up was presented to the court when it ruled on the suppression motion.
Likewise, we see no merit to the various arguments that the line-up was im-permissibly suggestive. As testimony heard on the suppression motion indicates, the defendants were themselves smiling, so that they did not stand out noticeably from the participants who were joking around; the defendants were given the chance to choose which set of hats and sunglasses they wanted to wear; and, finally, Johnson may have been asked to repeat “Hit the *460floor!” but only because he had spoken softly the first time.
Because the out-of-court identifications were sound, the in-court identifications need not be justified by any independent basis. If such a showing were required, however, the government has presented ample evidence of the reliability of the identifications under the relevant factors set out in Neil v. Biggers, 409 U.S. 188, 93 S.Ct. 375, 34 L.Ed.2d 401 (1972).
V
The appellants next contend that the admission into evidence of some semiautomatic weapon ammunition seized from the defendants' residence was error. They argue that even though the court later withdrew that evidence and instructed the jury to disregard that evidence, its previous admission was nonetheless so inflammatory that the cautionary instruction was inadequate to cure the prejudice caused.
Of course, the only issue is the adequacy of the curative instruction; any question of admissibility is irrelevant because the evidence was finally kept out. After testimony from an FBI agent that he did not know whether the ammunition seized could fit a revolver, the appellants successfully moved to have the previously admitted evidence excluded, and the court gave the following warning to the jury:
In that the court perceives no relationship to [sic] the box of ammunition to this case, the court has reconsidered its earlier ruling, admitting that item of evidence for your consideration.
And I’m now removing it from evidence. And I ask that you give it no consideration.
Joint Appendix at 126.
It appears that the appellants neither objected to this instruction nor requested any additional instructions. Even if the issue is properly before us, however, it lacks merit. The jury is generally presumed to be able to follow an instruction to disregard evidence, absent some strong indication that the evidence is so powerful that a jury could not ignore it and that the defendant would be harmed as a result. Green v. Miller, 483 U.S. 756, 107 S.Ct. 3102, 97 L.Ed.2d 618 (1987). In light of the abundant evidence against the defendants, there is no reasonable probability that the jury’s verdict was influenced by the jury’s seeing this later-excluded evidence. United States v. Barnes, 747 F.2d 246 (4th Cir.1984).
VI
The appellants next challenge the sufficiency of the evidence on their conviction under 18 U.S.C. § 924(c) for using a “firearm” to commit a violent federal crime. They contend that the only evidence that a firearm was used came from testimony of witnesses unfamiliar with firearms and from bank photographs. They argue that for a “firearm” conviction, at a minimum an expert should identify a firearm in bank photographs.
This argument is also without merit. The government need not present expert testimony to support a conviction under § 924(c). See Parker v. United States, 801 F.2d 1382 (D.C.Cir.1986). As five eyewitnesses testified that a gun was used in the robbery, there was evidence from which rational triers of fact could find guilt beyond a reasonable doubt on the firearms charge.
VII
Finally, at the sentencing hearing both defendants sought to challenge the constitutional validity of prior convictions that were expressly “counted” for purposes of classifying them as career offenders under United States Sentencing Guidelines § 4B1.1, which requires “at least two prior felony convictions of either a crime of violence or a controlled substance offense.” 1 The defendants’ challenges were *461brought pursuant to Guideline § 4A1.2, Application Note 6, which provides that “[c]onvietions which the defendant shows to have been constitutionally invalid may not be counted in the criminal history score.” Johnson’s challenge, filed as an objection to his presentence report, claimed that a 1983 New York state conviction named in the presentence report resulted from an involuntary guilty plea. Jones did not submit his challenge in an objection to his presentence report, but instead objected at the sentencing hearing to one of the prior convictions in his presentence report, asserting, as had Johnson, that it resulted from an involuntary guilty plea.
At the sentencing hearing, Johnson’s attorney proffered the facts of the allegedly involuntary guilty plea that led to the 1983 conviction and attempted to put Johnson on the stand to testify to the circumstances of the plea agreement. The district court refused to hear Johnson’s testimony, believing that it lacked the authority to entertain a collateral challenge to the constitutionality of the prior New York state conviction. The court stated that if Johnson wanted to invalidate the New York conviction and then argue for a reduced sentence on his current federal conviction, his remedy was to first challenge the state conviction by means of any available state postconviction procedures or, if appropriate, by application to the proper federal district court for a writ of habeas corpus. If the prior conviction was ultimately invalidated by a court with authority to entertain the collateral challenge, Johnson could at that point return to the court currently sentencing him and challenge the sentence on a motion under 28 U.S.C. § 2255. In any event, the district court concluded that it lacked the present authority to hear Johnson’s constitutional challenge to the prior conviction and on that ground declined to hear Johnson’s testimony. It later refused to hear Jones’ challenge on the same ground.2
A
The district court erred in thinking it lacked the power to entertain Johnson’s and Jones’ challenge. The court’s error lay in its perception that its jurisdiction to hear the challenges turned on satisfaction of the same prerequisites that apply to a habeas corpus application under 28 U.S.C. § 2254. It is true that, at first blush, the sentencing challenge procedure authorized by Guideline § 4A1.2, Application Note 6 bears a superficial resemblance to § 2254, for both procedures involve federal court inquiry into the validity of a prior state conviction. But the similarity extends no further.
In habeas corpus, the federal court may actually invalidate a state conviction and order the petitioner’s release from state custody. In light of this extraordinary power, federal habeas review of state criminal cases is significantly circumscribed by the complex body of rules and doctrines that protect, among other things, values of comity and finality in our federal system. Most critical, of course, is the very structure of the habeas proceeding in which the affected state, through its prisoner’s custodian, is effectively a party to the proceeding, hence able to defend its conviction against constitutional challenge. Incident to this is the further requirement imposed by the exhaustion requirement, see 28 *462U.S.C. § 2254(b), that the state shall first have had an opportunity to defend against the challenge in its own courts.
In federal sentencing' hearings, however, the exercise of federal judicial power as exemplified in its party structure is of an altogether different character. Involving only the United States and a federal defendant, it is limited to the federal court’s meting out an appropriate sentence for violation of a federal crime. To consider prior state convictions in making that determination involves no assertion of federal jurisdiction over a state criminal case, as occurs in a habeas corpus proceeding. The exercise of the federal judicial power to sentence in federal criminal cases raises questions not of federal jurisdiction but only of the proper exercise of the sentencing court’s discretion and the permissible breadth of the sentencing court’s inquiry.3
Congress has given clear directives on those questions. The sentencing court’s discretion is guided by the Sentencing Guidelines. See 18 U.S.C. § 8553(b) (“The court shall impose a sentence of the kind, and within the range” of the Sentencing Guidelines, unless the peculiar circumstances of the case warrant a departure from the Guidelines). Exercising discretion under the Guidelines, the court’s power to consider relevant information is unlimited. 18 U.S.C. § 3661 provides:
No limitation shall be placed on the information concerning the background, character, and conduct of a person convicted of an offense which a court of the United States may receive and consider for the purpose of imposing an appropriate sentence.
One type of information thought to be critical to accurate, uniform, and proportional sentencing is criminal history. See United States Sentencing Guidelines, Chapter Four, Part A “Criminal History,” Introductory Commentary (“A defendant’s record of past criminal conduct is directly relevant” to the aims of sentencing.).4 Hence, the Guidelines direct a sentencing court to take account of prior convictions — including prior state convictions — to structure the use of a defendant’s criminal history in sentencing. The critical question becomes one of Guidelines interpretation: How have the Guidelines structured the inquiry into criminal history? As explained more fully below, the general approach is that a court may “count” or assign points to certain prior convictions; other convictions may not be formally counted, but may be used as the basis for an upward departure when they reliably indicate past criminal activity. The district court in this case “counted" Johnson’s and Jones’ prior convictions, instead of using them as the basis for upward departures. We are thus confronted with a clearly presented, albeit unusually difficult, question of Guidelines interpretation: whether the Guidelines require the sentencing court to inquire into the validity of a challenged prior state conviction before formally “counting” that conviction in the computation of a defendant’s Criminal History Score or Career Offender status under Guidelines §§ 4A1.1, 4A1.2, and 4B1.1.
B
Some further explication of the use of a defendant’s criminal history under the Sentencing Guidelines is necessary to understand the narrow Guidelines interpretation issue presented. Under the Guidelines, a defendant’s “Criminal History Score” or *463status as a “Career Offender” determines his criminal history category, which, in turn, when plotted against the proper offense level, yields an applicable sentencing range. Section 4A1.1 of the Sentencing Guidelines governs the calculation of a defendant’s criminal history score, and § 4B1.1 defines career offender. Section 4A1.2 sets forth specific definitions and instructions applicable to the determinations made under §§ 4A1.1 and 4B1.1. See § 4B1.2 Commentary, Application note 4. The definitions and instructions in § 4A1.2 detail which criminal sentences and convictions may be “counted” in the Criminal History Score or the Career Offender designation. For instance, § 4A1.2(h) directs the sentencing court not to count “[s]en-tences resulting from foreign convictions,” and § 4A1.2(j) excludes from the calculation “[sentences for expunged convictions.” Those same subsections, however, permit a sentencing court to use the uncounted convictions as a basis for an upward departure in sentencing under § 4A1.3, whenever the court believes that “the criminal history category does not adequately reflect the seriousness of the defendant’s past criminal conduct.”
The Guidelines also forbid the counting of “invalid convictions,” but permit their consideration in making an upward departure under § 4A1.3 if they “provide reliable evidence of past criminal activity.” The Official Commentary to § 4A1.2, Application Note 6 states:
Sentences resulting from convictions that have been reversed or vacated because of errors of law, or because of subsequently-discovered evidence exonerating the defendant, are not to be counted. Any other sentence resulting in a valid conviction [sic] is to be counted in the criminal history score. Convictions which the defendant shows to have been constitutionally invalid may not be counted in the criminal history score. Also, if to count an uncounseled misdemeanor conviction would result in the imposition of a sentence of imprisonment under circumstances that would violate the United States Constitution, then such conviction shall not be counted in the criminal history score. Nonetheless, any conviction that is not counted in the criminal history score may be considered pursuant to § 4A1.3 if it provides reliable evidence of past criminal activity.
As noted, the district court in this case did not choose to make an upward departure under § 4A1.3, though that option would have been available if the court had found the prior convictions to be reliable evidence of past criminal activity. Had it so found, the upward departure probably would have resulted in the same sentence it imposed here. See § 4A1.3 (departure on ground that criminal history category underrepresented seriousness of criminal history should use as reference the otherwise applicable Guidelines sentence). Here, however, the district court formally “counted” the challenged convictions. The narrow question, then, is whether the district court misapplied § 4A1.2 by formally counting Johnson’s and Jones’ challenged prior convictions in the belief that it lacked the authority to entertain the challenge to their constitutional validity.
C
We have already held that § 4A1.2, Application Note 6 directs the sentencing court to entertain the precise kind of challenge that the district court in this case refused. In United States v. Davenport, 884 F.2d 121 (4th Cir.1989), the defendant challenged his classification as a Guidelines Career Offender on the ground that one of his prior state convictions was constitutionally invalid because he had never waived his right to a jury trial. When the defendant raised the challenge, the district court recessed the sentencing hearing and gave him four weeks to prepare his challenge to the prior conviction. At the later sentencing hearing, the court ruled against Davenport’s constitutional challenge to the pri- or conviction and accordingly used it in determining that he would be sentenced as a career offender.5
*464We affirmed the district court’s sentencing of Davenport as a career offender, holding that Davenport had not met his burden of showing that the prior conviction was constitutionally invalid. Id. In so holding, we nonetheless recognized that the part of § 4A1.2, Application Note 6 stating that “[c]onvictions which the defendant shows to have been constitutionally invalid may not be counted in the criminal history score” authorized the court to entertain the constitutional challenge that Davenport raised and that it put the burden of proof on the challenging defendant: “This Note is applicable in determining career offender status under 4B1.1, and it is clear from the plain language that the defendant has the burden of showing that a prior conviction is constitutionally invalid.” Davenport, 884 F.2d at 124. Other circuit courts had read § 4A1.2, Application Note 6 as we did in Davenport. See United States v. Dickens, 879 F.2d 410 (8th Cir.1989) (affirming district court’s ruling, after an evidentiary hearing before sentencing, that the defendant had failed to carry his burden that a prior conviction used in his criminal history score was the result of an involuntary guilty plea); United States v. Miller, 874 F.2d 466, 469 n. 5 (7th Cir.1989) (noting, in dicta, that “[tjhere may be times ... when a sentencing court will have to examine convictions to some degree if the defendant claims that the prior convictions are constitutionally invalid.”).
Nonetheless, the dissent would read Application Note 6 as permitting a sentencing court to treat as invalid challenged convictions only when the state court has already invalidated the conviction. This interpretation both disregards our holding in Davenport and is without foundation in the language of the Guidelines. The first sentence of Application Note 6 plainly instructs that previously invalidated convictions are not to be counted: “Sentences resulting from convictions that have been reversed or vacated because of errors of law, or because of subsequently-discovered evidence exonerating the defendant, are not to be counted.” In other words, the Guidelines already provide that convictions previously “show[nJ” to be invalid, whether in state postconviction proceedings or on federal habeas corpus, may not be “counted.” The separate language in the Application Note stating that “[cjonvictions which the defendant shows to have been constitutionally invalid may not be counted in the criminal history score” obviously contemplates a different opportunity to “show[ ]” a prior conviction’s constitutional invalidity. As we held in Davenport, that showing can come in the form of a challenge to a conviction not previously vacated or reversed.
Similarly, the dissent’s reading nullifies the Application Note’s clear directive that “if to count an uncounseled misdemeanor conviction would result in the imposition of a sentence of imprisonment under circumstances that would violate the United States Constitution, then such conviction shall not be counted in the criminal history score.” The theory of the dissent appears to be that it would be an impermissible expansion of federal judicial power for the sentencing court to determine that any state conviction — even one shown on its face to have been uncounseled — was invalid to the extent it might be used to increase a federal sentence. Such an arbitrarily restrictive view of the sentencing court’s power would deny the defendant his basic right, well established in the Supreme Court’s cases and safeguarded in the Guidelines, not to suffer an enhanced punishment predicated on the fact of a prior constitutionally invalid conviction. See Burgett v. Texas, 389 U.S. 109, 88 S.Ct. 258, 19 L.Ed.2d 319 (1967); United States v. Tucker, 404 U.S. 443, 92 S.Ct. 589, 30 L.Ed.2d 592 (1972).6
*465D
One might justifiably be concerned that-this interpretation of the Guidelines could result in unduly protracted or delayed sen-tencings, inconvenient reexamination of old convictions from far-flung jurisdictions, and immobility in the criminal justice system. But the Guidelines are carefully structured to avoid these potential problems. The dissent’s parade of these horri-bles is simply illusory in light of two critical features of the Guidelines not adequately taken into account in the dissent: the sentencing court’s power to impose procedural requirements for the presentation of disputed sentencing factors and its power to make an upward departure.7
The Guidelines contemplate that the pre-sentence report will serve the crucial function of addressing all information relevant to sentencing, hence obviating the need for delays or prolonged hearings. Section 6A1.1 mandates that a parole officer prepare for the court a presentence report, unless the court finds on the record that it already has sufficient information meaningfully to exercise its sentencing power. The defendant may not waive this report. The Official Commentary to § 6A1.1 emphasizes the Sentencing Commission’s view that the new sentencing system’s effectiveness is critically dependent on a “thorough presentence investigation ... determining the facts relevant to sentencing.” Detailed information about prior convictions that may be used in sentencing should be and usually is provided in the presentence report, giving the court a sufficient basis for its inquiry into the validity of the convictions.
The presentence report also serves the important function of putting the defendant on notice of any prior convictions that might be used in sentencing. A sentencing court would be free to insist that the defendant, aware of the contents of the presen-tence report, make a timely objection to the validity of any prior conviction in the report or else waive that objection. Section 6A1.2 expressly notes and encourages use of the district courts’ authority to adopt rules to aid the orderly presentation of such challenges:
Courts should adopt procedures to provide for the timely disclosure of the pre-sentence report; the narrowing and resolution, where feasible, of issues in dispute in advance of the sentencing hearing; and the identification for the court of issues remaining in dispute.
In sum, while a sentencing court may not arbitrarily disregard a challenge to a prior conviction, nothing about our holding is meant to suggest that the court would not have broad discretion, within bounds of due process, to control the manner of the challenge’s presentation.
Second, the dissent fails to appreciate the substantial flexibility afforded the sentencing court by § 4A1.3, which embodies an invitation by the Sentencing Commission to depart upward based on conduct underlying even an invalid, or arguably so, convic*466tion. The practical effect of the challenge permitted in § 4A1.2, Application Note 6 is qualified by the last sentence of the Application Note: “Nonetheless, any conviction that is not counted in the criminal history score may be considered pursuant to § 4A1.3 if it provides reliable evidence of past criminal activity.” Section 4A1.3 is carefully tailored to avoid the incongruity of requiring a court to ignore a defendant’s serious criminal past because of the fortuity that he might be able to keep certain prior convictions from being “counted.” Towards that end, § 4A1.3 invites departure “[i]f reliable information indicates that the criminal history category does not adequately reflect the seriousness of the defendant’s past criminal conduct or the likelihood that the defendant will commit other crimes.” Such departures have regularly been upheld by the courts of appeals. See, e.g., United States v. Sturgis, 869 F.2d 54 (2d Cir.1989); United States v. Geiger, 891 F.2d 512 (5th Cir.1989); United States v. Belanger, 892 F.2d 473 (6th Cir.1989); United States v. Dorsey, 888 F.2d 79 (11th Cir.1989).
Furthermore, a departure under this provision will often result in the same sentence that would have been imposed had the invalid conviction been counted. If the court is satisfied that the criminal history score “significantly under-represents the seriousness of the defendant’s criminal history, and that the seriousness of the defendant’s criminal history most closely resembles” that of defendants in the higher category that would have resulted from counting the invalid conviction, then that higher category should guide the court’s discretion in setting the sentence. The only effect of using § 4A1.3 is to require some separate inquiry into the conduct underlying the prior conviction, beyond its automatic counting, but there is no reason to think that such an inquiry would necessitate anything more than an examination of the presentence report. Like the Seventh Circuit, “[w]e anticipate that it will become usual practice to include in presentence reports sufficient detail about prior criminal conduct, including that not resulting in conviction, in order to assist the court in determining ‘the variations in the seriousness of criminal history that may occur.’ ” United States v. Miller, 874 F.2d 466, 469 (7th Cir.1989) (quoting Guidelines § 4A1.3, commentary at 4.10).
The distinction between the impermissible counting of an invalid prior conviction and the permissible use of the conduct underlying that conviction in an upward departure is consistent with the Supreme Court’s decision in United States v. Tucker, 404 U.S. 443, 92 S.Ct. 589, 30 L.Ed.2d 592 (1972). In that case, the Supreme Court ordered a remand for resentencing where the district judge had given explicit attention in sentencing to three prior convictions later invalidated by Gideon v. Wainwright, 372 U.S. 335, 83 S.Ct. 792, 9 L.Ed.2d 799 (1963). The Court ordered the remand because the sentence had not been “imposed in the informed discretion of [the] trial judge, but [was] founded at least in part upon misinformation of a constitutional magnitude.” Tucker, 404 U.S. at 447, 92 S.Ct. at 591-92. The Court, however, emphasized that the judge would have been well within his discretion in considering the conduct that underlay the previous convictions: “a judge may appropriately conduct an inquiry broad in scope, largely unlimited either as to the kind of information he may consider, or the source from which it may come.” Id. at 446, 92 S.Ct. at 591 (citations omitted). Indeed, the dissent in Tucker did not take issue with the majority’s exposition of sentencing law, but only with its conclusion that the fact of the prior conviction was material to the sentence. Id. at 449-50, 92 S.Ct. at 592-93. The dissent noted that the judge would almost certainly impose the same sentence on remand, a possibility that the majority acknowledged would be a wholly permissible exercise of discretion. Id. at 452, 92 S.Ct. at 594. In other words, Tucker rested squarely on the distinction between the impermissible mechanical counting of the fact of an unconstitutional conviction and the permissible consideration of that conviction’s reliable evidence of prior criminal activity.
In permitting the sentencing court to treat as invalid some prior convictions and *467so not to “count” them in the criminal history score, the Sentencing Commission has not, as the dissent charges, sought to expand the courts’ jurisdiction; it has not even broadened the traditional scope of the permissible sentencing considerations. See Tucker, 404 U.S. at 447, 92 S.Ct. at 591. Indeed, the Sentencing Commission acted well within its congressional authorization when it directed courts to inquire into the validity of prior convictions. As noted, Congress has expressly provided that for ■purposes of federal sentencing there is no statutory limitation on the breadth of the sentencing court’s inquiry:
No limitation shall be placed on the information concerning the background, character, and conduct of a person convicted of an offense which a court of the United States may receive and consider for the purpose of imposing an appropriate sentence.
18 U.S.C. § 3661; see Guideline § 1B1.4. The congressional formulation of 18 U.S.C. § 3661 simply reflects the Tucker Court’s recognition of the importance of fully informed sentencing. One potentially critical piece of information, as Tucker recognized, is whether the defendant had previously been validly convicted. But, as 18 U.S.C. § 3661 dictates, the conclusion that the defendant’s prior conviction was not a valid one does not disable a court from considering other relevant information concerning, the prior conviction.
Section 4A1.2 is a perfect example of the Sentencing Commission’s attempt to guide the sentencing court’s discretion in evaluating prior convictions, one type of information in the universe of potentially relevant sentencing factors. In essence, § 4A1.2 merely formalizes what was once a more informal, probably often unarticulated, judicial reliance on prior convictions. As examination of the interaction between Guidelines §§ 4A1.2 and 4A1.3 shows, reliance on—by formal counting—a valid prior conviction is permissible without further inquiry; when a procedurally proper challenge to a prior conviction is made, however, the court must either satisfy itself of the conviction’s validity or use it in an upward departure if circumstances so warrant. Put another way, those Guidelines sections have neither limited nor expanded the reach of the sentencing court’s traditional and statutory power to consider prior convictions, but have instead simply required a more rigorous, and honest, exercise of that power—they provide the “guidelines” whereby the sentencing court can assure itself of “informed discretion” and avoid the possibility of sentencing based “upon misinformation of a constitutional magnitude.” Tucker, 404 U.S. at 447, 92 S.Ct. at 592.8
E
Read in context, § 4A1.2, Application Note 6 provides for some kind of opportunity, which can be shaped by local procedural rules, to challenge a possibly invalid prior conviction before its use in sentencing. Unlike 28 U.S.C. § 2254(b), governing habeas corpus, Application Note 6 contains no exhaustion requirement. The dissent, however, would have us read such a requirement into the language of the Guidelines. To do so in the teeth of Congress’ mandate to apply the Guidelines as written would both contravene legislative intent and frustrate the careful scheme of §§ 4A1.2 and 4A1.3 and Application Note 6.
We have previously rejected the notion that a court could impose an exhaustion requirement when Congress had provided for an opportunity to challenge an allegedly invalid prior conviction before its use in sentencing. In United States v. Scarborough, 777 F.2d 175 (4th Cir.1985), the defendant was to be sentenced under the now-repealed “Dangerous Special Offender” statute, 18 U.S.C. § 3575, which permitted enhanced sentences for certain repeat offenders, but provided the defendant an *468opportunity to challenge any prior conviction relied on in the sentence enhancement. Under 18 U.S.C. § 3575(e), “[a] conviction shown on direct or collateral review or at the sentencing hearing to be invalid” was to be disregarded in determining whether the defendant was subject to the enhanced sentence. In Scarborough, the defendant had attempted to show at the sentencing hearing that one of his prior convictions was invalid because it rested on evidence gained in an unlawful search and because there had been insufficient evidence to support the conviction. We held that the district court erred in refusing even to hear the challenge on the ground that the conviction could still be attacked in habeas corpus proceedings. Specifically, we noted that the statute “clearly contemplate[d] some sort of review of the validity of a prior conviction,” id. at 181, and that it permitted such a challenge to be brought “at the hearing.” Like the old Dangerous Special Offender statute, Application Note 6 contemplates some opportunity to “show” the invalidity of a prior conviction — whether state procedures have been exhausted or not — through means other than habeas corpus. As noted, to read that provision otherwise simply disregards its telling first sentence, which already forbids counting of reversed or vacated convictions.
It is true that we have in the past found it appropriate to impose an exhaustion requirement where to do so would not frustrate the legislative intent of a sentencing scheme. Specifically, we have imposed an exhaustion requirement on a motion under 28 U.S.C. § 2255 when the petitioner seeks to use the motion as a vehicle to attack state convictions. In United States v. Gaylor, 828 F.2d 253 (4th Cir.1987), we refused to permit a petitioner to bring in a § 2255 motion an unexhausted challenge to a state conviction after he had foregone his clear opportunity to raise that challenge at his Dangerous Special Offender hearing. Although we noted that no exhaustion requirement had been codified in § 2255, we found the judicial imposition of such a requirement necessary to safeguard comity concerns. Id. at 255. See also Brown v. United States, 483 F.2d 116 (4th Cir.1973) (judicial imposition of exhaustion requirement on § 2255 motion claiming that un-counseled state convictions had been used as sentencing factor). We emphasized in Gaylor, however, that where Congress has evinced an intent that exhaustion should not be required before the challenge could be brought, as in the Dangerous Special Offender hearing, Congress’ disregard of exhaustion must be respected. Id. at 256. We found in Gaylor and Brown that § 2255 evinced no such congressional intent to permit foregoing exhaustion and accordingly we required exhaustion in that context to protect comity values.
Here, we deal with a situation, as in Scarborough, where Congress has directed courts to examine the prior convictions as an incident to using them in sentencing. Congress’ clear intent to establish through the Sentencing Guidelines a scheme for accurate, uniform, and proportional sentencing, evident in the language of Application Note 6 and the interaction between §§ 4A1.2 and 4A1.3, has overridden whatever comity concerns might otherwise be present when using state convictions as evidence of criminal history in federal sentencing for federal crimes. As in Scarborough, a judicially-created exhaustion requirement in this context would contravene the legislative intent to resolve disputed sentencing factors at the time of sentencing, a concern not present in Gaylor and Brown.
F
The conclusion we reach might nevertheless give us pause if the sentencing court’s determination that a prior state conviction could not be “counted” under the Guidelines would effectively invalidate the state conviction before exhaustion of state remedies. But, of course, it would not. It is important in analyzing the nature of the defendant’s challenge under the sentencing procedure here in issue to emphasize again its narrowness and limited consequences. The issue it presents is a narrow one: can a prior state conviction be “counted” in a criminal history score or *469career offender determination? By law, it may not be if it is then shown to be “constitutionally invalid.” A negative answer would not entitle a defendant who is still in custody on the prior conviction to automatic release. He has not, as in habeas, sued his custodian for unconstitutional confinement, but has merely interposed a defensive challenge to a particular factor sought to be used against him in current sentencing for another offense. Nor would a finding of constitutional invalidity for this limited purpose have preclusive effect in a later state or federal habeas proceeding, because the defendant’s custodian, hence the state, will not have been a party (unless by sought intervention) to the federal sentencing proceeding. Cf. Hamlin v. Warren, 664 F.2d 29 (4th Cir.1981) (exhaustion of prisoner’s § 1983 claim against state officials required where same claim against same defendants would entitle successful prisoner-plaintiff to release from custody if claim had been brought as habeas petition).
G
Finally, the dissent’s claim that to read the Guidelines as we do here — and as we already have in Davenport — would create undue burdens on sentencing courts is misconceived. First, as noted, a court’s ability to adopt procedures to hear such challenges and to make upward departures can substantially facilitate the proper (and constitutional) consideration of prior convictions. Second, to require exhaustion, apart from disregarding the language of the Guidelines, would create a set of burdens on the state and federal court systems that the dissent does not acknowledge. Take a simple case of an uncounseled prior conviction sought to be used to increase the criminal history score of a federal defendant. While the sentencing court might have to resolve other much more difficult disputed sentencing factors, it would be forbidden from considering the validity of the prior conviction at the sentencing hearing. Then, even where the invalidity of the prior conviction was apparent to the federal court, the defendant would have to litigate that issue in state post-conviction proceedings and, if necessary, on federal habeas corpus under § 2254. Finally, the defendant would then have to reengage the federal sentencing court, at some time likely to be far removed from the initial sentencing hearing, on a § 2255 motion. The point is clear enough: even in the simplest of cases, the dissent’s litigious approach would mandate at least one set of state proceedings and at least one extra round of federal review.9 Such an untoward result might have to be tolerated if comity concerns so dictated. But those concerns are not actually present here, as the court’s determination has no effect beyond the federal sentencing itself, cf. Hamlin v. Warren, and, more critically, because Congress has determined that they shall not control the federal sentencing process, cf. Scarborough.
VIII
For the reasons stated in Parts I-VI, we affirm the district court’s judgments of conviction. For the reasons stated in Part VII, however, we vacate the sentences imposed by the court and remand for resen-tencing not inconsistent with this opinion. On remand, the district court should first determine whether the defendants’ challenges were properly presented under the court’s procedures. If so, the court should give the defendants such opportunity to present evidence concerning the prior convictions as the court deems necessary to a meaningful exercise of its sentencing authority. See Guideline § 6A1.1. Only if the court then finds that the defendants have failed to meet their Davenport burden of showing the invalidity of the challenged prior convictions may it count the convictions for purposes of criminal history score or career offender status. If the defendants do carry their Davenport bur*470den, the court may nonetheless consider making an upward departure under § 4A1.3 if it finds that the defendants’ prior convictions provide reliable evidence of past criminal activity.
AFFIRMED IN PART; VACATED AND REMANDED IN PART.
. Defendant Jones also challenged his conviction on the ground that it should not have been classified an adult offense for sentencing purposes. This contention is meritless, as he does not dispute that the offense qualifies as an adult offense under the literal language of the Guidelines.
. The record indicates that Johnson would probably have had an alternative forum in which to challenge the prior conviction he sought to attack. According to his presentence report, he is in custody on the 1983 New York state conviction, inasmuch as he has absconded from New York parole for that conviction, and a parole violation warrant is outstanding. See Jones v. Cunningham, 371 U.S. 236, 83 S.Ct. 373, 9 L.Ed.2d 285 (1963). Jones, on the other hand, apparently would not have had another forum in which to challenge the 1978 conviction used as part of his career offender calculation. His presentence report indicates that, although he is in custody on a separate 1981 state conviction by virtue of a detainer lodged by New York, he has been released from custody and parole has lapsed on the 1978 conviction he sought to challenge. He is not "in custody” on the 1978 conviction merely by virtue of the fact that it is being used to enhance his present sentence. See Maleng v. Cook, — U.S. -, 109 S.Ct. 1923, 1926, 104 L.Ed.2d 540 (1989) (per curiam). This distinction between the defendants’ status, however, is immaterial in light of our resolution below of the issue of the district court’s authority to entertain their challenges.
. The dissent would nonetheless read § 3661 as permitting consideration of factors relating only to the "person” of the defendant, as opposed to the defendant's past criminal conduct. See Op. at 474. This metaphysical distinction is nowhere to be found in the language of the statute, which refers expressly to a defendant's "conduct," nor in the Guidelines themselves, which place critical reliance on criminal history.
. Despite the fact that the district court in Davenport heard evidence to determine, for sentenc*464ing purposes, the validity of a prior conviction — a decision we affirmed — the dissent makes the curious assertion that “Davenport is silent on the central issue of who has the power to determine validity." Op. at 473 n. 4.
. Though not an official statement of the Sentencing Commission and not legally binding, the Sentencing Commission’s publication "Questions Most Frequently Asked About the Sentencing Guidelines” provides an illuminating and persuasive interpretation of Application Note 6. In particular, it illustrates that the common sense of the Application Note is that a sentencing court must have the power to make some *465appropriate inquiry into prior convictions before "counting” them:
74. QUESTION: Are prior uncounseled convictions considered invalid convictions and therefore not countable under criminal history?
ANSWER: Not necessarily. If a conviction was constitutionally invalid, it is not counted in the criminal history score. (See § 4A1.2, Application Note 6.) However, the fact that a conviction was uncounseled does not automatically mean that the conviction was constitutionally invalid. In the case of a felony or misdemeanor, for example, the defendant may have waived counsel. Or, in the case of a misdemeanor, a term of imprisonment may not have been imposed and thus provision of counsel would not have been constitutionally required.
Appellate courts have held that evidence of a standard practice or customary procedure in a particular jurisdiction can be used to establish the probable constitutional validity of a prior conviction. Courts have also held that the defendant must carry the burden of establishing the invalidity of a prior conviction when the government demonstrates habit and custom that meet constitutional standards. (See, e.g. United States v. Dickens, 879 F.2d 410 (8th Cir.1989); United States v. Davenport, 884 F.2d 121 (4th Cir.1989).)
. The concern about consideration of old convictions is also mitigated by § 4A1.2(e), which forbids counting all fifteen-year-old sentences, and ten-year-old sentences of less than one year imprisonment.
. Contrary to the dissent’s rhetorical assertion that we have ”sanction[ed] a limitless, standard-less, subjective inquiry into a defendant’s background,” Op. at 477, we take as our basic premise that the Guidelines have significantly constrained the sentencing court’s discretion. The issue, as the dissent refuses to recognize in its zeal to rhapsodize on larger themes, is not whether, but how, that discretion has been constrained in the Guidelines.
. The dissent's dire prediction that our holding will lead to "an avalanche of hearings” contesting prior convictions, Op. at 481, bespeaks the odd assumption that defendants whose sentences have been substantially enhanced by arguably invalid convictions would not, if the sentencing court does not hear them, bring about an even greater “avalanche" of state postconviction proceedings, § 2254 petitions, and — finally —§ 2255 motions.