In August of 1864 Ralph Graham of Brooklyn, N.Y., patented this "...new and useful Improvement in Firearms for Projecting Grenades or Small Bomb-Shells." Graham applied for his patent in October of 1863, and why it took the Patent Office nearly a year to issue the final paperwork is uncertain. The basic principle was not new---British Brown Bess flintlock muskets with detachable muzzle cups predate 1750---but (based on the text of his patent) Graham's embodiment was handier and easier to use. Were any built beyond the prototype stage? Who knows?