The accompanying factory letter lists this revolver as chambered in .45 Eley Short (.450 Boxer) and blue finish while not listing the barrel length or grip. The revolver was shipped on October 11, 1877 to Colt's London Agency, London, England. Per R.L. Wilson in "The Book of Colt Firearms", just over 3,400 standard Colt SAAs were chambered in .450 Eley/Boxer. The top of the barrel is stamped with the Colt Pall Mall London address. The left side of the frame has the three-line patent dates marking. The caliber marking "45 CAL/B" is stamped on the left side of the trigger guard. London proofs are stamped on the underside of the barrel and behind each cylinder chamber. The ejector rod has a bullseye head. Matching full or partial serial numbers appear on the frame, trigger guard, back strap, cylinder, and barrel. The partitioned case has an "E.T.B." marked brass initial inlay on the exterior of the lid, Colt London paper label on the interior of the lid, empty cartridge block, and cleaning rod.