Andrew James Dennis appeals from a guidelines sentence of twenty-seven months following his guilty plea to possession of an unregistered firearm. We affirm.

Dennis first claims the district court erroneously increased his offense level under U.S.S.G. Sec. 2K2.2(b)(1)(B) for distributing six firearms although he was indicted for possessing only a single sawed-off shotgun. We disagree. In drug cases, this court has sanctioned the use of uncharged but relevant conduct to calculate offense levels, and has held the amount of drugs involved and the relevancy of conduct are factual findings reversible only on clear error. See, e.g., United States v. Lawrence, 915 F.2d 402, 406-08 (8th Cir.1990); United States v. Gooden, 892 F.2d 725, 727-29 (8th Cir.1989), cert. denied, --- U.S. ----, 110 S. Ct. 2594, 110 L. Ed. 2d 274 (1990). Although Dennis possessed and distributed guns rather than drugs, we believe the same rationale applies regardless of the contraband involved. Having reviewed the record, we find no clear error.

Dennis next argues increasing his offense level for possessing a stolen weapon, see U.S.S.G. Sec. 2K2.2(b)(2), subjects him to double jeopardy because he is serving a state sentence for receiving stolen property that included the sawed-off shotgun. This argument is without merit. Both the federal government and a state may prosecute and punish an offender for the same conduct, and the dual punishment by separate sovereigns does not mean an offender " 'has been twice punished for the same offense; but only that by one act, he has committed two offenses, for each of which he is justly punished.' " Heath v. Alabama, 474 U.S. 82, 88, 106 S. Ct. 433, 437, 88 L. Ed. 2d 387 (1985) (quoting Moore v. Illinois, 14 How. 13, 19, 14 L. Ed. 306 (1852)).

Finally, Dennis argues the district court should have granted him credit for time served on his state sentence. A defendant is entitled to credit for time spent in official detention only if it has not been credited against another sentence. See 18 U.S.C. Sec. 3585(b) (1988). In this case, Dennis receives credit on his state sentence for the time he spends in state custody. Thus, Dennis is not entitled to credit this time against his federal sentence.

Accordingly, we affirm.