Don't get too wrapped up in Army/Navy designation. Here's a couple quotes on the subject:
The 'Army' and 'Navy' designations cannot reliably be used to determine the branch in which the weapon saw service. Both were used interchangeably by each service. As a matter of fact, the Army bought more of the Colt Navy model than did the Navy.
R.L.Wilson: The designation "Colt 1851 Navy" was applied by collectors, though the popular name "Navy Revolver" is of early origin, as the gun was frequently called the "Colt Revolving Belt Pistol of Naval Caliber.
Despite the "Navy" designation, the revolver was chiefly purchased by civilians and military land forces(ibid Wilson 1985)."
The 'Army' and 'Navy' designations cannot reliably be used to determine the branch in which the weapon saw service. Both were used interchangeably by each service. As a matter of fact, the Army bought more of the Colt Navy model than did the Navy.
R.L.Wilson: The designation "Colt 1851 Navy" was applied by collectors, though the popular name "Navy Revolver" is of early origin, as the gun was frequently called the "Colt Revolving Belt Pistol of Naval Caliber.
Despite the "Navy" designation, the revolver was chiefly purchased by civilians and military land forces(ibid Wilson 1985)."