Francisco B. Lopez, federal prisoner # 56053-079, appeals the district court’s *467 denial of his 28 U.S.C. § 2241 petition, in which he challenged the way the Bureau of Prisons (BOP) is crediting the time he has served on a 72-month federal sentence and a 240-month federal sentence. Lopez argues that the BOP should back date the commencement of his 240-month sentence to coincide with the date he began serving his 72-month sentence. He contends that because the offenses are related, he can serve no more than the 240-month sentence imposed as a result of his second conviction. He argues that by refusing to credit the time he has served on his 72-month sentence toward the service of his 240-month sentence, his' punishment for those offenses is being illegally cumulated.

To the extent that Lopez attempts to raise claims cognizable in a 28 U.S.C. § 2255 motion, the district court was without jurisdiction to entertain them. See § 2255. Accordingly, Lopez is not entitled to relief based on those claims.

With regard to his remaining claims, Lopez has not shown that the district court erred by denying his § 2241 petition. See 18 U.S.C. § 3585(a) & (b). Accordingly, the judgment is AFFIRMED.