Darnell Brown, Jr., pled guilty to a conspiracy drug offense involving distribution of marijuana and possession with intent to distribute and distribution of 5 grams or more of cocaine base after being convicted of a felony drug offense. The district court1 sentenced Brown to 360 months and he appeals, arguing that there were several sentencing errors and that his sixth amendment right to effective assistance of counsel was violated. We affirm.
Brown was part of a conspiracy to sell cocaine base or crack and marijuana in Cedar Rapids, Iowa. Shauntella Hopkins, Michael Clark, and Rondesha Roundtree were involved in the same conspiracy. Clark had been Brown’s friend since childhood and had traveled with him from Chicago to Cedar Rapids a few weeks before a confidential informant made controlled buys in April 2005. The two men stayed in Hopkins’s apartment while in Cedar Rapids; she is the mother of Brown’s young daughter. Roundtree was a high school student with ties to Iregous Parks, a drug trafficker doing business in the area.
The confidential informant arranged to buy drugs from Brown, whom he knew as “P,” through calls to Brown’s cell phone. The first two sales occurred on April 12 and 14 in Hopkins’s apartment, which is within 1000 feet of a public high school and a playground, and she was present for both. These sales involved about 2.08 grams of crack and 2.7 grams of marijuana.2 Brown also agreed to sell the confidential informant $300 worth of crack on April 21. He called Roundtree, who was carrying a cell phone and keeping crack for Iregous Parks. She agreed to supply the crack for Brown’s sale which was to occur in the parking lot of a local grocery store. Brown, Roundtree, and Clark went there together in Brown’s car. Clark drove, Brown sat in the passenger seat, and Roundtree sat in the back with the crack. The informant approached Brown, handed him $300 in recorded currency, *837and Brown passed him about 2.47 grams of crack.
After the sale Clark drove to a nearby convenience store and went in to buy some items, paying with one of the $10 bills that the confidential informant had given Brown. While Brown and Roundtree were waiting for him, the police arrived and arrested Brown on an outstanding warrant. As he was being arrested, Brown asked Roundtree if she had his money, and the police found $290 and $537 on her after she waived her Miranda rights.3 Clark consented to a search of the car, and officers found a bag of crack in the trunk near where Roundtree had been sitting. The bag contained about 4.97 grams of crack. Later that day officers executed a search warrant at the apartment where Brown had been staying with Hopkins. They found two guns and some ammunition in the bedroom shared by Hopkins and Brown. Although Brown denied owning the firearms, he had access to the weapons and there was some evidence that he had handled and possessed them.
Brown, Clark, Hopkins, and Roundtree were charged in an eight count indictment on May 4, 2006. Brown was named in all eight counts and faced charges of conspiracy, felon in possession of a firearm and ammunition, possession with intent to distribute crack and distribution of crack, and distribution of marijuana. At his arraignment Brown pled not guilty to all counts, and he was detained pending trial. Defense counsel was appointed in May 2006. On June 22, 2006 Brown participated in a proffer interview in which he admitted that he had regularly sold cocaine, crack, and marijuana from approximately June 2003 until his April 2005 arrest. Brown states that he had not realized that this information could be used against him. Although his attorney had provided him with a copy of the proffer agreement, he says he has substantial difficulty reading and mistakenly believed it was a plea agreement. In August 2006 Brown filed a pro se motion for new counsel, which the district court granted after a hearing.
On defense counsel’s motion Brown underwent an evaluation to help determine his competency for trial. During his psychological examination Brown indicated that he had experienced physical and sexual abuse as a child and had run away from home to escape the abuse; he also reported a long history of alcohol and drug use. Brown was found competent to stand trial and to assist in his own defense, but the January 18, 2007 psychological report diagnosed him with antisocial personality disorder, polysubstance dependence, and depressive disorder not otherwise specified, although medical staff suspected that his psychotic symptoms were due to malingering. Brown reported taking prescription medications for depression and paranoia.
Meanwhile, Brown’s codefendants had entered into plea agreements and provided information against him. Brown decided to negotiate a plea agreement with the government and changed his plea to guilty on Count 1, which charged a conspiracy to distribute marijuana and to possess with intent to distribute and distribute 5 grams or more of cocaine base after being convicted of a felony drug offense. In exchange the government agreed to dismiss the remaining charges. The district court accepted Brown’s plea and conducted a sentencing hearing on December 21, 2007 *838and January 3, 2008. Several witnesses testified, including Brown, Clark, Round-tree, Mario Williams, a fellow inmate of Brown’s, and Agent Moyle, an officer who had interviewed Brown.
After hearing testimony and arguments, the district court calculated Brown’s advisory guideline sentencing range. Brown’s drug quantity was based on the average daily sales of cocaine and crack he had admitted in his debriefing interview for the period between June 2003 and April 2005. He was ultimately held responsible for 935 grams of cocaine base and 354 grams of cocaine, which amounted to 5,680.80 kg of marijuana equivalents pursuant to § 2D1.1 of the United States Sentencing Guidelines Manual (U.S.S.G.). Because the sales had occurred within 1000 feet of a protected location, his base offense level was 35 under U.S.S.G §§ 2D1.1 and 2D1.2. The district court imposed a two level increase for possession of a dangerous weapon during the offense, a two level increase for Brown’s supervising role in the offense, and a two level increase for obstruction of justice. The court denied Brown’s request for a two level downward adjustment for acceptance of responsibility. With an adjusted offense level of 41 and criminal history category III, his guideline sentencing range was 360 months to life. Brown requested a downward departure or variance based on his mental and emotional condition, his history of child abuse, and his illiteracy, and the government requested an upward departure or variance. After denying both motions, the district court imposed a sentence of 360 months, at the bottom of the guideline range.
Brown appeals his sentence, arguing that the district court made several sentencing errors, that the sentence imposed is unreasonably long, and that he was denied his sixth amendment right to effective assistance of counsel. The government denies each of the alleged sentencing errors, and it argues that his 360 month sentence is not unreasonable and that his ineffective assistance of counsel claim is not ripe for review.
Brown first challenges the district court’s imposition of a two level increase in his offense level based on his organizing role in the offense, arguing that there was no evidence that he exercised the requisite control and authority over another participant. The government contends that Clark’s evidence that he served as Brown’s driver for drug transactions and received little remuneration sufficiently supported the increase. We review the upward adjustment of Brown’s sentence based upon his aggravating role for clear error, see United States v. Jimenez-Gutierrez, 425 F.3d 1123, 1124 (8th Cir.2005), and under this standard we will reverse only if we have a “definite and firm conviction” that the district court made a mistake. United States v. Willis, 433 F.3d 634, 636 (8th Cir.2006) (quotation omitted).
The district court determined that Clark had been led, managed, or supervised by Brown and therefore increased his offense level pursuant to U.S.S.G. § 3Bl.l(c). That section provides for a two level increase in the offense level if the defendant was “an organizer, leader, manager, or supervisor in any criminal activity” which involved fewer than five participants, and we broadly construe the terms manager or supervisor. See U.S.S.G. § 3Bl.l(c); United States v. Rosas, 486 F.3d 374, 376-77 (8th Cir.2007). Clark testified at the sentencing hearing that he had driven Brown to several drug transactions in Cedar Rapids and in Davenport, Iowa. Explaining the events on the day of the third controlled buy, Clark said that he was helping Hopkins move a TV when Brown called and “told” Clark to “come get him,” without telling him why, “so [Clark] had *839left to go get him,” and then drove him to the deal. On this record, we are satisfied that the district court neither clearly erred in determining that Brown had played an organizing role in the offense nor in enhancing his sentence on that basis. See United States v. Maejia, 928 F.2d 810, 816 (8th Cir.1991) (affirming organizing role enhancement for defendant who recruited two drivers for drug deal); United States v. Zimmer, 299 F.3d 710, 724 (8th Cir. 2002) (management or supervision of only one other participant or one transaction suffices for organizing role enhancement).
Brown also contends that the district court erred by enhancing his sentence for obstruction of justice under U.S.S.G. § 3C1.1, suggesting his false testimony was immaterial to the sentencing issues and may have been due to a mistake or faulty memory. The government argues that the increase was appropriate and that Brown’s falsehoods under oath were neither mistaken nor immaterial.
We review the district court’s factual findings underlying an adjustment for obstruction of justice for clear error, giving great deference to the sentencing court’s determination. See United States v. Whiting, 522 F.3d 845, 849 (8th Cir. 2008).4 Under U.S.S.G. § 3C1.1 a defendant is subject to a two level enhancement if he “testifies falsely under oath in regard to a material matter and does so willfully rather than out of confusion or mistake.” United States v. Mendoza-Gonzalez, 363 F.3d 788, 796 (8th Cir.2004); see also United States v. Dunnigan, 507 U.S. 87, 94-95, 113 S.Ct. 1111, 122 L.Ed.2d 445 (1993); U.S.S.G. § 3C1.1 comment, n. 4. When a defendant objects to an obstruction enhancement based on perjury, the district court must make findings that the defendant willfully gave false testimony concerning a material matter in the case. Mendoza-Gonzalez, 363 F.3d at 796; see also Whiting, 522 F.3d at 850.
The district court determined that Brown had lied under oath at the sentencing hearing and that his lie was material because it was an attempt to discredit Mario Williams, a government witness. Brown was a suspect in the shooting of a man known as Boo Man, and Williams testified that Brown had asked him to help him falsely implicate a man known as Shoo Boo in that shooting with the hope of obtaining a sentencing decrease.5 Brown contradicted Williams’s testimony, stating “I don’t even know no Shoo Boo. I never even heard of him.” Agent Moyle subsequently testified that Brown had told him during an interview on May 14, 2007 that *840he knew Shoo Boo, that he had provided a physical description of Shoo Boo, and that he had said that Shoo Boo used rental cars to sell crack. Nothing in the record indicates that Brown’s emphatic denial of knowing Shoo Boo was due to faulty memory or mistake. Brown argues that his statements about Shoo Boo are not material because they did not substantially affect the case’s outcome, but for purposes of the obstruction enhancement a material statement is one which “if believed, would tend to influence or affect the issue under determination.” U.S.S.G. § 3C1.1 comment, n. 6.
The issue under determination here was whether to apply an obstruction of justice enhancement. If the district court had believed Brown’s false testimony, that could have influenced its view of the credibility of the other witnesses at sentencing and its understanding of facts relevant to an appropriate sentence for his case.6 The district court found that Brown willfully provided false testimony at sentencing. -In explaining why Brown’s lie was material the court explained, “[Brown] testified under oath before this Court that he didn’t know Shoo Boo, never heard of him. Now, one would think that’s kind of a — sort of beside the point, but it was very material in this sentencing, because by denying that he knew Shoo Boo, he was attempting to discredit Mr. Williams’ testimony, who was also a witness at this sentencing. And of course, Mr. Williams is the one who testified about alleged statements defendant made about the shooting that we’ve been arguing about and for which the government has been seeking enhanced penalties. So it’s very material in this case, lying to this Court under oath, about if he knew Shoo Boo.” As this passage suggests, the most plausible reason for Brown to lie about knowing Shoo Boo was to try to avoid the obstruction of justice enhancement sought by the government, a different theory than the one ultimately adopted by the district court itself. See United States v. Flores, 959 F.2d 83, 87 (8th Cir. 1992) (“[Ljying for the purpose of obtaining a lighter sentence constitutes obstruction of justice within the meaning of section 3C1.1.”) (citations omitted); see also United States v. Kessler, 321 F.3d 699, 703 (8th Cir.2003) (“We have affirmed a district court’s finding of perjury and subsequent application of sentence enhancements for obstruction of justice where the perjured testimony directly contravened testimony of other witnesses ....”) (citations omitted). The district court was able to judge Brown’s testimony in light of all the evidence, and we conclude that it did not clearly err in applying an adjustment for obstruction of justice.
Brown further argues that the district court wrongly denied his requested downward adjustment for acceptance of responsibility under U.S.S.G. § 3E1.1, arguing that his guilty plea and cooperation with authorities entitles him to this reduc*841tion. We review a district court’s factual determination on whether a defendant has demonstrated acceptance of responsibility for clear error, giving the decision great deference. United States v. Brandt, 419 F.3d 810, 812 (8th Cir.2005); see also U.S.S.G. § 3E1.1 comment, n. 5 (“The sentencing judge is in a unique position to evaluate a defendant’s acceptance of responsibility.”). An obstruction of justice enhancement under § 3C1.1, such as Brown received, “ordinarily indicates that the defendant has not accepted responsibility for his criminal conduct” as required for a § 3E1.1 reduction. U.S.S.G. § 3E1.1 comment, n. 4; see also United States v. Calderon-Avila, 322 F.3d 505, 508 (8th Cir.2003) (per curiam). Although there may be “extraordinary cases” in which both adjustments apply, U.S.S.G. § 3E1.1 comment, n. 4, a case in which “a reduction for acceptance of responsibility is warranted in spite of a defendant’s obstructive conduct ‘would be extremely rare.’ ” United States v. Perez, 270 F.3d 737, 739 (8th Cir.2001), quoting United States v. Honken, 184 F.3d 961, 969 (8th Cir.1999). To determine whether a case is “extraordinary,” a district court should consider “the totality of the circumstances, including the nature of the appellee’s obstructive conduct and the degree of appellee’s acceptance of responsibility.” Honken, 184 F.3d at 968.
The district court determined that Brown did not qualify for an acceptance of responsibility reduction because he had lied to the court during the sentencing hearing on a material matter. To establish an extraordinary case for purposes of § 3E1.1, a defendant “must show more than a guilty plea and a cessation of obstructive conduct.” Honken, 184 F.3d at 970. Brown’s false testimony occurred after his guilty plea, and “post-plea obstructive conduct would almost certainly be disqualifying.” Id. Moreover, his plea agreement and cooperation with authorities do not distinguish his case from a run of the mill case. See id. (“Virtually every defendant who receives an acceptance of responsibility adjustment enters a plea of guilty.”). We therefore see no clear error in the district court’s denial of a § 3E1.1 adjustment.
Brown next objects to the district court’s denial of his motion for a downward departure or variance and argues that his sentence is unreasonably long. His request for a departure or variance was based on his mental and emotional disorders, the physical and sexual abuse he suffered as a child, and his difficulty reading and writing. A sentencing court’s discretionary decision not to depart downward is not generally reviewable ón appeal, however, and Brown does not allege that the district court had an unconstitutional motive or mistakenly believed it lacked authority to grant the departure. See United States v. Johnson, 517 F.3d 1020, 1023 (8th Cir.2008); see also United States v. Rice, 332 F.3d 538, 540 (8th Cir. 2003). We therefore decline to review the district court’s denial of the departure. After reviewing all the circumstances of this case and the sentencing transcript, we conclude that the district court did not abuse its discretion in denying Brown’s request for a downward variance. See United States v. Allebach, 526 F.3d 385, 388 (8th Cir.2008).
We review the sentence imposed for reasonableness, first “ensuring] that the district court committed no significant procedural error.” Gall v. United States, — U.S.-, 128 S.Ct. 586, 597, 169 L.Ed.2d 445 (2007); see also Whiting, 522 F.3d at 849. If the district court’s decision is “procedurally sound,” we proceed to review the sentence for substantive reasonableness under an abuse of discretion stan*842dard. Gall, 128 S.Ct. at 597; Whiting, 522 F.3d at 849. We may apply a presumption of reasonableness to a sentence within the properly calculated guideline range but are not required to do so. See Rita v. United States, — U.S.-, 127 S.Ct. 2456, 2465, 168 L.Ed.2d 203 (2007); Gall, 128 S.Ct. at 597; Whiting, 522 F.3d at 849. In imposing a sentence under 18 U.S.C. § 3553(a), a sentencing court abuses its discretion if “it fails to consider a relevant factor that should have received significant weight, gives significant weight to an improper or irrelevant factor, or considers only the appropriate factors but commits a clear error of judgment in weighing those factors.” United States v. Watson, 480 F.3d 1175, 1177 (8th Cir.2007).
The district court correctly calculated Brown’s advisory guideline range and imposed a 360 month sentence which fell at the very bottom of the range. It considered all of the relevant factors under § 3553(a), commenting that Brown’s criminal history category of III understated his long and serious criminal history and noting that Brown had a high risk of recidivism. We conclude that the sentence imposed “accounted for the seriousness and breadth” of Brown’s offenses and is not unreasonable. See United States v. Kowal, 527 F.3d 741, 749 (8th Cir.2008).
Finally, Brown contends that his prior attorney was constitutionally ineffective. Brown asserts that the attorney should have explained the terms and consequences of the proffer agreement to him but instead improperly assumed that he could read it on his own. Brown claims to be functionally illiterate, and he alleges that his attorney’s omissions led him to mistake the proffer agreement for a plea agreement and that he then he admitted substantial drug dealing during his proffer interview. These admissions increased his drug quantity by nearly a hundredfold and triggered a substantially longer sentence. Ineffective assistance of counsel claims are better raised under 28 U.S.C. § 2255, however. United States v. Cook, 356 F.3d 913, 919 (8th Cir.2004). Although such a claim may be properly considered on direct appeal “where the record has been fully developed, where counsel’s ineffectiveness is readily apparent, or where to delay consideration of the claim would lead to a plain miscarriage of justice,” United States v. Davis, 452 F.3d 991, 994 (8th Cir.2006), none of those exceptional circumstances pertain here and the record has not yet been developed. See id. Accordingly, this claim is premature and would be more appropriately raised in a post conviction proceeding under § 2255.
For the foregoing reasons, we affirm the judgment of the district court.
. The Honorable Linda R. Reade, Chief Judge, United States District Court for the Northern District of Iowa.
. Brown claims that the marijuana was sold solely by Hopkins, but the stipulated facts in his plea agreement stated that the marijuana was purchased from both Brown and Hopkins.
. Although Roundtree initially told police that the money belonged to Brown, she later testified that she had been carrying some money for Parks in her bra. As the police approached, Brown threw her the money from the controlled sale. She stuffed that money in her bra and the crack in the trunk of the car.
. While the interpretation of the sentencing guidelines is subject to de novo review, United States v. Minnis, 489 F.3d 325, 333 (8th Cir. 2007), whether a defendant "commitfs] perjury and in so doing obstruct[s] justice is a factual finding, and thus we will reverse the district court’s imposition of a sentence enhancement under U.S.S.G. § 3C1.1 only upon a showing of clear error.” United States v. Kessler, 321 F.3d 699, 702-03 (8th Cir.2003), citing United States v. Esparza, 291 F.3d 1052, 1054 (8th Cir.2002); cf. United States v. Armilio, 705 F.2d 939, 941 (8th Cir.1983) (although materiality under 18 U.S.C. § 1623 is a question of law, its proper determination “depends upon the factual situation in which the testimony was given.”) (quotation omitted).
. Although Williams testified that Brown told him to say that Deonte Williams shot Boo Man, the overall plan was to "tell on Shoo Boo.” As Williams explained, "So [Brown] said, 'You just say that Deonte shot him. You say Deonte shot him. So when we pull Deonte in it, that's going to lead to pulling Shoo Boo in it' ... and it will lead to the arrest of Shoo Boo.” When asked why Brown wanted Williams to provide this false information to the government, Williams said, "it would basically coincide ... with what he told them, and it would make it ... seem true....”
. The government offered at least three theories for why an obstruction of justice increase was appropriate, and Williams' testimony was relevant to all three. First, Williams testified that Brown had told him that he shot Boo Man himself which supported the government's theory that Brown falsely denied involvement in that shooting. Second, Williams testified that Brown asked him to give false information that Deonte Williams had shot Boo Man, which supported the government's theory that Brown had asked others to provide false information. Third, Williams testified that Brown had approached him with his fists up and ready to fight in the jail the morning before the sentencing hearing; that supported the government’s theory that Brown committed perjury by falsely denying his threatening behavior. Although the district court did not accept any of the government's theories in applying the obstruction of justice enhancement, Brown could not have known that at the time he lied about knowing Shoo Boo.