Does attaching a silencer to a shotgun constitute a crime?

U.S.S.G. 1B1.3(a). The attachment of the silencer was part of the same course of conduct as the manufacture and possession of the shotgun. It furthered the crime and, in fact, may have dramatically escalated the risk of harm. This "uncharged but relevant conduct" is appropriate to use in calculating the specific offense characteristics under 2k2.2(b). Cf. United States v. Dennis, 926 F.2d 768, 769 (8th Cir.1991) (approving consideration of uncharged weapons under current section 2K2.2(b), governing trafficking in firearms). Furthermore, amendments to the relevant conduct section of the guidelines lend support to the interpretation of the guidelines by the district court.