The factory letter lists this revolver in ".45 Eley" with a 5 1/2 inch barrel and blue finish when it was part of a shipment of 50 of these revolvers shipped to Colt's London Agency at 14 Pall Mall on July 29, 1878. ".45 Eley" and ".45 Boxer" appear to have been used interchangeably by Colt as is clearly shown on this revolver which letters in ".45 Eley" but is marked ".45 CAL/B" on the left side of the trigger guard. There are also several other names for the official designated ".450 Boxer Mk I" cartridge that was adopted for the centerfire Adams revolvers in 1868, including ".450 Colt." The barrel has the scarce "COLT'S PT. F.A. MFG Co HARTFORD CT. U.S.A. DEPOT 14 PALL MALL LONDON" address and has a blade front sight. Only 1,653 Model 1878s were manufactured in .450 Boxer with a 5 1/2 inch barrel and blue finish per Don Wilkerson in "Colt's Double-Action Revolver" on p. 354. London proofs are stamped on the underside of the barrel and behind each cylinder flute. The cylinder, loading gate, toe, and both grip panels have matching serial numbers. The partitioned oak case features green baize lining, a Colt London Agency trade label on the interior of the lid, an L-shaped screwdriver, a cleaning rod, and a 21-round cartridge block with 6 fired cartridge cases and 13 cartridges with various head stamps, including some from Eley.

Exceptionally fine with 85% plus bright original high polish blue finish, some flaked areas displaying smooth brown patina, and generally only light age and storage related wear. The grips are excellent and have crisp checkering, nearly all of the high polish finish, and minor handling and storage marks. Mechanically excellent. The case and accessories are very fine and have minor age and storage related wear. This is a very impressive Colt London Agency cased Model 1878 DA revolver from the first year of production.