The purpose of rifling is to impart a spin to a projectile as it is thrust through the air in order to stabilize it and allow it to be more accurate.
Superior Boer marksmanship and Mauser rifles exacted a high price from the British during the Second Anglo-Boer War, 1899-1902. But the Boers used other arms as well—everything from single-shots to "Long" Lee-Enfields.
From the February 1982 American Rifleman, learn the history of the first silencer, invented by Hiram P. Maxim.
Among the calibers that came from the military is the 7x57 mm Mauser.