Charles Edward Phillips pleaded guilty to possession of an unregistered firearm, a shotgun having a barrel length of less then 18 inches, a violation of 26 U.S.C. § 5861(d). Phillips was sentenced to 41 months of imprisonment and three years *966 of supervised release. Phillips now appeals, challenging only his sentence.

Citing Blakely v. Washington, 542 U.S. 296, 124 S.Ct. 2531, 159 L.Ed.2d 403 (2004), and United States v. Booker, — U.S.-, 125 S.Ct. 738, 756, 160 L.Ed.2d 621 (2005), Phillips argues that the district court erred when it enhanced his offense level by four pursuant to U.S.S.G. § 2K2.1(b)(5) because the firearm was possessed in connection with another felony offense, the possession of methamphetamine. Under Booker, the judicially determined enhancement, made under a mandatory guideline regime, violated his Sixth Amendment right to a trial by jury. Booker, 125 S.Ct. at 756.

Where, as here, a defendant has preserved a Booker issue in the district court, “we will ordinarily vacate the sentence and remand, unless we can say the error is harmless under Rule 52(a) of the Federal Rules of Criminal Procedure.” United States v. Mares, 402 F.3d 511, 520 n. 9 (5th Cir. 2005), petition for cert. filed, No. 04-9517 (U.S. March 31, 2005). The Government concedes that it cannot demonstrate that the Booker error is harmless because it cannot show beyond a reasonable doubt that the mandatory nature of the guidelines did not contribute to the Phillips’s sentence. See United States v. Akpan, 407 F.3d 360, 376-77 (5th Cir. 2005). Accordingly, we vacate Phillips’s sentence and remand for resentencing. See id.

VACATE SENTENCE; REMAND FOR RESENTENCING.