discussed Cited "see" United States v. Trotter This court has used the “fortress theory” in determining the applicability of § 2K2.1(b)(5), the theory being that there is a sufficient connection between a firearm and a drug offense when “it reasonably appears that the firearm[ ] ... [is] to be used to protect the drugs or otherwise facilitate a drug transaction.” Ennenga, 263 F.3d at 503 (internal quotation marks omitted); see United States v. Hardin, 248 F.3d 489, 500 (6th Cir.), cert. denied, 534 U.S. 920 , 122 S.Ct. 271 , 151 L.Ed.2d 199 (2001). 1 In the case at bar, where a semi-automatic handgun was loaded and placed within e…