Like most persons in these threads, General Robert E. Lee most likely had a number of personal firearms, but the one most closely associated with him was his Colt 1851 Navy, in .36 caliber. Rumor has it this gun was loaded and sealed with beeswax shortly before death, subsequently it was fired 7 years afterward and all charges were reported to have gone off! It currently resides in the American Civil War museum in Richmond. Particulars of the gun are ported to be as follows:
Colt Model 1851 Navy Revolver, 3rd Model - .36 cal., 6-shot cylinder, 7.5" octagonal barrel. Outfitted with a brass post front sight, rear sight through V-notch in hammer. Case hardened frame, hammer, and loading lever with rest of gun being blued. One piece walnut grip, silver plated brass trigger guard and back strap. Markings as follows - Barrel at top: - ADDRESS SAM'L COLT NEW-YORK CITY - Frame, left side: COLTS / PATENT / U.S; serial number 37698
Reportedly, Lee carried this gun in a saddle pommel holster when on horseback, and his holster also resides in the museum.
There are many replicas of this famous revolver, many available as cased sets.