Neat find. There were cannons with bronze barrels. Percussion caps weren't invented until 1836, so your find dates between then and the Civil War, when advances in fire arms rapidly occurred. Those types of pistols were called "muff pistols." Ladies used to keep their hands warm using large fur muffs. Those pistols were very convenient to carry in a muff for self protection. Gentlemen also carried them as hide out guns for self defense. Note, the gun does not have a ram rod. Those guns weren't fired for fun or target shooting. There were stores where once a week or so, a gentleman or lady could stop by, shoot the gun into a barrel, and then the gunsmith would clean and reload the gun for him, so there was always a "fresh charge" in the gun.