The Mannlicher-Carcano was an Italian military rifle from the late nineteenth century, named after Count Ferdinand Mannlicher
and Salvatore Carcano
, respectively designer of the rifle's magazine system and head of the Italian team who created the action. It is famous nowadays for two things. Firstly, of all the advanced bolt-action designs fielded at the time, it used the smallest-calibre smokeless
cartridge, 6.5x52mm rather than the 7.5-11mm cartridges used elsewhere. Although less powerful than other cartridges, it was felt that this was immaterial, as the bullets could still kill a man at a great distance. During the century that followed, small-calibre rounds became the mainstream and remain so today, indeed many theorise that the current generation of NATO 5.56mm cartridges should be slightly larger.
The Mannlicher-Carcano is famous for another thing. John F Kennedy was killed by a bullet fired from a Carcano. Whether the trigger was pulled by Lee Harvey Oswald, the Cigarette-Smoking Man or Kennedy himself, it is an accepted fact that Kennedy's motorcade was the target of three 6.5mm bullets fired from a Carcano. The first struck the road, missing Kennedy's car. The second and third bullets did not miss. Back and to the left.
The Mannlicher-Carcano is more accurately called the M91, for it was adopted into Italian service in 1891 as the standard arm of the infantry and, in shorter form, as a cavalry weapon. Certain rifles are iconic, the Carcano is not. The Mannlicher-Carcano's very first combat deployment, in 1898, was against the citizens of Milan, rioting over a 'flour tax' which had greatly increased the price of bread. Under a certain General Bava Beccaris, Italian troops shot dead anything from 100-400 protestors; not the kind of event to inspire much affection for the Carcano. The Italy army's performance in the First World War went un-noticed by the outside world, whilst its experiences in the Second World War were generally disastrous, this failure reflecting badly on the army's equipment. There is no compelling reason for owning a Carcano nowadays; Oswald bought his because they were extremely cheap at the time. The modern equivalent would be a surplus SKS, a semi-automatic design with plentiful and cheap ammunition.
In 1938 the Italian army fielded a shorter, modified version of the basic M91 Carcano, called the M38, chambered for a now-rare 7.35x51mm cartridge which was not a success, thanks in part to the Second World War. The complexities of supplying two calibres of ammunition led to subsequent designs being chambered for 6.5mm again. The majority of Carcanos had fixed sights, set at 200-300 metres depending on model. As with all military rifles of the period it was capable of hitting and killing a man at twice this distance (Oswald's fatal shots were fired from roughly 80 metres away).
The Carcano's magazine was fed from clips. The six rounds that its magazine held were gripped by a metal clip until the last round was fed into the chamber, at which point the clip was released from the bottom of the magazine to fall to the ground in a manner similar to the French Lebel rifles of WW1. Carcano ammunition was designed before the advent of the 'spitzer' (pointed) rifle bullet and remained torpedo-shaped throughout its life; it is still manufactured today as a speciality item, although the only other weapon to use the 6.5 Carcano round was the Breda light machine-gun of the Great War. The Carcano used progressive rifling, a system whereby the frequency of the barrel's rifling increased as it reached the muzzle.
Oswald's Carcano was a 6.5mm M91/38 (the rifle design dates from 1891, generally modified into a shorter carbine in 1938), serial number C2766, equipped with a cheap four-power scope with an 18mm objective lens, the lowest of the low. Prior to shooting Kennedy, Oswald posed for a set of famous photographs in his back yard, holding his Carcano and a copy of a communist newspaper. Much has been made of these pictures, of Oswald's pose, of the relative length of the rifle and of Oswald's body, all of which is outside the scope of this writeup. All the facts presented at the beginning of this paragraph are doubted, to an extent that one might as well argue that Kennedy's head flapped open from blocked sinuses rather than a bullet impact (a theory suggested by the funniest writeup on Everything2) Initially, the CIA identified the rifle as a 7.65mm Mauser, a considerably more successful rifle design.
After WW2 the Italian army, such as was left of it, adopted the American M1 Garand in .30-06. In the late 1950s Italy replaced this with the 7.62x51mm BM-59, a modified Garand; the Italian peacekeepers you see on the television news now use Beretta's AR-70/90 in 5.56x45mm NATO.