 The initial .303 Mark I and Mk II service cartridges employed a 215-grain, round-nosed, copper-nickel full-metal-jacketed bullet with a lead core.After tests determined that the service bullet had too thin a jacket when used with cordite, the Mk II bullet was introduced, with a flat base and thicker copper-nickel jacket.The Mk II round-nosed bullet was found to be unsatisfactory when used in combat, particularly when compared to the dum-dum rounds issued in limited numbers in 1897 during the Chitral and Tirah expeditions of 1897/98 on the North West Frontier of India.