The bullet appears to be an unfired 1870s/80s .44-40 bullet for Winchester Model-1873 Rifle or Marlin Rifle, manufactured by Winchester. Here's a photo of an original 1890s packet of them, except these are hollow-nose, and they have "reeding" or "knurling" in the bullet's body-grooves.
The bullet appears to be an unfired 1870s/80s .44-40 bullet