Colt used "Army" and "Navy" purely as marketing terms. The first Colts, the Paterson model, used by the Texas Navy were .36 caliber. When the US Navy ordered '51 Colts in .36 caliber they were called the "Navy Model" (by the way, Colt never made a '51 in .44 caliber). When the 1860 came out in .44 it was called the "Army Model", but both services bought and used both revolvers. Given all that, the hysterically-minded nitpickers like me want "Army" to mean a .44 and "Navy" to mean a .36, and the idea of a .36 Army makes us break out in hives. Pass the calomine lotion...