 Like the .450 Black Powder Express, the .577/500 BPE came in several case lengths, the most common having a 3-inch case.A 3⅛-inch variant would later be loaded with cordite to become the .577/500 Nitro Express.For some time the .577/500 No 2 BPE was loaded with cordite to become the .577/500 No 2 Nitro for Black, the same cartridge loaded with mild loadings of cordite, carefully balanced through trial to replicate the ballistics of the Black powder version.