Henry Martini was a single shot breech loaded rifle used by the British during late 1800’s. It was a good weapon in those times. The under-leaver located at the pistol grip would open the breech for loading a single round. The caliber is a whopping .577 inches! I am sure it must have made a big bang when fired. Over a period of time various versions were produced. The smaller one made to be carried by horsemen was called a musket.