This revolver is pictured and discussed on pages 100 and 101 of "The Book of Colt Firearms" by R.L. Wilson who notes that among the Hartford-English Dragoons "is a Second Model (Serial #156) which the authors consider as so rare it is an extremely unique manufacturing entity. The mainspring is of the V pattern, yet the hammer is fitted with a roller bearing. Furthermore the trigger guard is of the wide-bottomed design common to the early First Dragoons." Wilson indicates it was then part of the Robert Q. Sutherland Collection. Very few of the Hartford-English Dragoons are known to still exist out of approximately 700 believed to have been manufactured in c. 1853-1857. Most have the Third Model trigger guard. 200 remained in Colt's stock in London at the outbreak of the Civil War and were shipped back to Hartford along with thousands of other arms on-hand. This revolver has the engraved rather than stamped "COLT'S/PATENT" marking on the left side of the frame that was standard on the guns assembled and finished in London from parts manufactured at the Hartford plant. The barrel has a brass blade front sight and "{ADDRESS SAML COLT NEW-YORK CITY}," and both the barrel and cylinder have London proof and view marks. The cylinder also has the U.S.M.R. roll-scene. Matching serial numbers are located on the loading lever, barrel ("2" also marked above), wedge, cylinder pin, cylinder, frame, trigger guard, back strap, and grip in the back mortise. The right side of the grip has "C1" at the top and a cannon looking mark over "MA/1510" on the bottom. This revolver is discussed in detail in "Colonel Colt London: History of Colt's London Firearms, 1851-1857" by James G. Rosa on pages 140 and 141.