proportionality is not mandated by the Constitution. See United States v. Layne, 324 F.3d 464, 474 (6th Cir.2003). IV. For the reasons stated, defendant’s convictions and sentences are AFFIRMED. 1 . Defendant had entered a guilty plea, which he successfully moved to withdraw. 2 . Section 924(c) criminalizes two distinct offenses: using or carrying a firearm during and in relation to a drug offense, and possessing a firearm in furtherance of a drug offense. United States v. Combs, 369 F.3d 925, 933 (6th Cir.2004). Only the latter was charged in this case. 3 . The government also argues that proof of a sufficient nexus is further supported by evidence that defendant took a firearm from Coon in partial payment for heroin. United States v. Frederick, 406 F.3d 754, 764 (6th Cir.2005) (<HOLDING>). Defendant points out that, although Coon's
holding that the placement of a loaded weapon on the drivers seat of a car carrying drug instrumentalities was sufficient evidence of possession in furtherance of a crime holding that trading drugs for a gun violates the in furtherance of prong of  924c holding that large amount of cocaine packaged in individual baggies was one basis for affirming conviction for possession of a firearm in furtherance of a drug trafficking offense holding that in a prosecution for possession of an unregistered firearm evidence of an armed robbery committed with the firearm was admissible holding that acquisition of a firearm in exchange for drugs is a sufficient nexus to establish possession in furtherance of the drug sale