I did some research on this type of bullet. The base is conical and the gas seal rings with the ridges in them dates the bullet between 1870-1880 when black powder was used in the first modern cartridges. Modern bullets do not have the same type of gas seal rings, they have a crimp ring and the base is flat. Most modern bullets are copper jacketed and the ones that are lead do not have enough time to achieve the patina that this one shows.