states: “It shall be unlawful for any person ... to receive or possess a firearm which is not registered to him in the National Firearms Registration and Transfer Record.” From the text of the statute, the only element is possession of an unregistered firearm. However, the Supreme Court has read a mens rea requirement into the crime — to obtain a conviction, the Government must prove the defendant “knew of the features of [the firearm] that brought it within the scope of the Act.” Staples v. United States, 511 U.S. 600, 619, 114 S.Ct. 1793, 128 L.Ed.2d 608 (1994). Dwyer contends that because “the gravamen of the offense ... is the lack of registmtion th Cir.) (same), cert. denied, 528 U.S. 958, 120 S.Ct. 388, 145 L.Ed.2d 303 (1999); United States v. Fortes, 141 F.3d 1, 7 (1st Cir.1998) (<HOLDING>); United States v. Dunn, 946 F.2d 615 (9th
holding that possession of sawedoff shotgun is violent felony as defined by armed career criminal act holding that ohios thirddegree burglary statute constituted a violent felony under the residual clause of the armed career criminal act holding that possession of a shortbarreled shotgun is a violent felony under the accas residual clause because sawedoff shotguns are inherently dangerous and lack usefulness except for violent and criminal purposes internal quotation marks omitted holding that the illinois crime of failure to report for imprisonment is not a violent felony for purposes of the armed career criminal act holding that for purposes of  4b12 possession of a sawedoff shotgun in violation of  5861d is a crime of violence because by its very nature a sawedoff shotgun always creates a serious risk of physical injury to another