The 6.5×52mm Carcano, also known as the 6.5×52mm Parravicini–Carcano or 6.5×52mm Mannlicher–Carcano, is an Italian military 6.5 mm (.268 cal, actually 0.2675 inches) rimless bottle-necked rifle cartridge, developed from 1889 to 1891 and used in the Carcano 1891 rifle and many of its successors. Under the direction of the Commissione delle Armi Portatili (commission for portable weapons), instituted in 1888, to develop a smokeless-powder rifle for the Italian Army, the Reale Laboratorio Pirotecnico di Bologna (royal pyrotechnical laboratory of Bologna) developed and tried several different cartridge designs, with bullet diameters from 6 to 8mm. Finally, due also to the influence of Major Antonio Benedetti of the Brescia Arsenal, secretary of the commission and strong supporter of the advantages of smallbore cartridges, the 6.5×52 cartridge was adopted in March 1890, prior to the adoption of the rifle that used it (the Model 1891 Carcano rifle).
The cartridge is acceptable, with proper bullet, for medium-size big game such as North American whitetail deer within 250 yards. However, the standard Italian service round used an unstable round-nosed bullet with a propensity to tumble, whether hitting soft tissue/ballistic gel or harder material such as bone.
It has been found that the cartridge is indeed accurate and the rifles were well constructed. Cartridge developers and experimental handloaders such as P.O. Ackley found the rifle was able to handle excess pressure, with even Ackley’s abuse “unable to break the action.” A testament to the quality of the rifle and the cartridge.