 Rifled flintlocks saw most military use by sharpshooters, skirmishers, and other support units.While by the late 18th century there were increasing efforts to take advantage of the rifle for military purposes, with specialist rifle units such as the King's Royal Rifle Corps of 1756 and Rifle Brigade (Prince Consort's Own), smoothbores predominated until the advent of the Minié ball – by which time the percussion cap had made the flintlock obsolete.Because of the time needed to reload (even experts needed 15 seconds to reload a smooth-bore, muzzle-loading musket), flintlocks were sometimes produced with two, three, four or more barrels for multiple shots.