John Terrell Mosely, federal prisoner # 31171-034, is serving a 104-month term of imprisonment for distribution of cocaine base (crack). He appeals the district court’s denial of his 18 U.S.C. § 3582(c)(2) motion, in which he sought a sentence reduction pursuant to the Fair Sentencing Act (FSA) and Amendment 750 to U.S.S.G. § 2D1.1. The district court dénied the *512 motion on the ground that at sentencing, it had applied the 18:1 crack-to-powder ratio in determining Mosely’s sentencing guidelines range. See Dorsey v. United States, — U.S.-,-, 132 S.Ct. 2321, 2329, 183 L.Ed.2d 250 (2012) (“[The FSA] had the effect of lowering the [previous] 100-to-1 crack-to-powder ratio to 18-to-l.”). Mosely contends that (1) his 104-month term of imprisonment was based on a guidelines range that was amended by Amendment 750; (2) because the Sentencing Guidelines are advisory, the district court had the discretion to resentence him based on a 1:1 crack-to-powder ratio; and (3) the district court had the discretion to impose a “comparable reduction” in light of U.S.S.G. § 1B1.10(b)(2)(B), p.s., and the Supreme Court’s decision in Freeman v. United States, — U.S. -, 131 S.Ct. 2685, 180 L.Ed.2d 519 (2011).

Section 3582(c)(2) permits the discretionary modification of a defendant’s sentence “in the case of a defendant who has been sentenced to a term of imprisonment based on a sentencing range that has subsequently been lowered by the Sentencing Commission pursuant to 28 U.S.C. [§ ]994(o).” § 3582(c)(2); see United States v. Doublin, 572 F.3d 235, 237 (5th Cir. 2009). The district court’s decision whether to reduce a sentence under § 3582(c)(2) is reviewed for an abuse of discretion, and its interpretation of the Guidelines is reviewed de novo. United States v. Henderson, 636 F.3d 713, 717 (5th Cir. 2011).

Mosely’s base offense level at the time of sentencing was 28, and it was unchanged at the time he filed his § 3582(c)(2) motion. See U.S.S.G. § 2Dl.l(c)(6). Thus, the district court had no authority to reduce Mosely’s sentence under § 3582(c)(2). See U.S.S.G. § 1B1.10(a)(2)(B); see Dillon v. United States, 560 U.S. 817, 826-27, 130 S.Ct. 2683, 177 L.Ed.2d 271 (2010). Because Mosely’s sentencing range was not lowered, Mosely’s reliance on § lB1.10(b)(2)(B) is unavailing. Further, Freeman is inapposite as it concerned whether a defendant who was sentenced pursuant to a binding plea agreement was barred from seeking a sentence reduction under § 3582(c)(2). See Freeman, 131 S.Ct. at 2692-95.

To the extent that Mosely argues that the district court had the discretion to resentence him based on a 1:1 crack-to-powder ratio, his argument is unpersuasive; a § 3582(c)(2) proceeding is not a full resentencing or an opportunity to challenge the original sentence. See Dillon, 560 U.S. at 825-31, 130 S.Ct. 2683; Doublin, 572 F.3d at 238. The principles of United States v. Booker, 543 U.S. 220, 125 S.Ct. 738, 160 L.Ed.2d 621 (2005), and its progeny do not apply to § 3582(c)(2) proceedings, and a sentencing court lacks discretion to reduce a sentence further than the reduction allowed pursuant to § 1B1.10. Dillon, 560 U.S. at 825-31, 130 S.Ct. 2683; Doublin, 572 F.3d at 237-39.

AFFIRMED.