In terms of different ammunition the Martini was trialed with various improvements to the thin paper like crinkly brass case variant that was infamous for jamming in the breach. See
http://thebiggamehuntingblog.com/201...ritish-empire/ for an interesting page of detail on the rounds.
Below a belt of my own ammo for the Martini Henry, A british Infantryman with the weapon, a 3 d Image of the system and the evolving ammunition ending with the 303 on the right..