Dist. Ct. erred in sentencing defendant to 160-month term of incarceration on unlawful possession of firearm charges, where said sentence was based in part on 4-level, “other felony offense” enhancement under section 2K2.1(b)(6)(B) of USSG. Dist. Ct. improperly applied both trafficking enhancement and “other felony offense” enhancements, where both enhancements were based on same conduct concerning defendant’s transfer of firearms to third-party, with knowledge that third-party was going to resell said firearms. Ct. rejected govt. claim that application of “other felony offense” enhancement was proper since defendant’s transfer of firearms occurred in connection with felonies other than firearm trafficking offense.