Here is a .30 caliber teflon-coated cartridge. It is an AP from Frankford Arsenal and, yes, it is entirely green colored. I assume the teflon coating was to help feeding in automatic arms.
Does anybody have a model number or experiment number for this cartridge and any history? Was this for a general purpose weapon like the M1 or Browning MG or was there a special weapon in mind when it was being tested? Any information would be much appreciated.