; (C) the possession, by an individual who is retired from service with a law enforcement agency and is not otherwise prohibited from receiving ammunition, of a large capacity ammunition feeding device transferred to the individual by the agency upon that retirement; or (D) a manufacture, transfer, or possession of a large capacity ammunition feeding device by a licensed manufacturer or licensed importer for the purposes of testing or experimentation authorized by the Attorney General. . (c) Penalties Section 924(a) of such title is amended by adding at the end the following: (8) Whoever knowingly violates section 922(v) shall be fined under this title, imprisoned not more than 10 years, or both. . (d) Identification markings Section 923(i) of such title is amended by adding at the end the following: A large capacity ammunition feeding device manufactured after the date of the enactment of this sentence shall be identified by a serial number that clearly shows that the device was manufactured after such date of enactment, and such other identification as the Attorney General may by regulation prescribe. .