This is an old gun that my grandmother (born in 1916) says belonged to her grandfather in the 1800's in Indiana. There are no obvious marks/words inscribed on it. She doesn't know how he got it, but she thinks that the end of the muzzle was sawed off, and may have been even longer. She or someone once told me that it may have been a flintlock, converted to use percussion caps. Any help with identifying its make and year is appreciated.