Mackey pleaded guilty to being a felon in possession of a firearm and received a 15-year ACCA sentence based in part on two Florida concealed-firearm convictions. After Begay and later circuit precedent, he argued that those convictions no longer qualified as ACCA violent felonies; because he had already litigated a § 2255 motion, he sought relief through § 2241’s savings clause. The district court denied the petition because it treated the savings clause as unavailable for a challenge to a sentence rather than the underlying conviction. Applying Bryant’s five-part test, the Eleventh Circuit held that circuit precedent had foreclosed the claim through Mackey’s first § 2255 proceeding, Begay applied retroactively, and the resulting sentence exceeded the otherwise applicable 10-year maximum, so § 2255(e) allowed § 2241 relief. The court vacated the denial and directed the district court to reduce Mackey’s 180-month prison term to 10 years and his four-year supervised-release term to three. Judge Martin agreed that the savings clause allowed relief and that a reduction without resentencing was appropriate, but dissented from the majority’s timing rule, which required circuit foreclosure at sentencing and on direct appeal as well as during the first § 2255 proceeding.