The reason for the gain twist in the Carcano rifle had nothing to do with accuracy. The clever boys in the Italian munitions plant were seeking to find a way to satisfy the Genevea Convention prohibition against exploding, or dum-dum, and hollow point expanding bullets, by making their bullets, while technically in compliance with the international convention, TUMBLE because they were over stabilized by the faster rate of twist as the bullet left the muzzle. This allowed them to have a flat trajectory , but when the bullet struck flesh, it would tend to tumble, cause the same massive wounds, that the Geneva Convention was trying to prevent by banning hollow points and other expanding bullets. The cartridge was adopted back in 1891. In 1936, when the Italian Army began its expansion, and needed more rifles, the old guns in poor shape were rebarreled with straight rifled barrels, and the new, shorter Carbines were also barreled with the stright rifled barrels. No one knows what rifling is in the rifle used to shoot President Kennedy in 1963, and the Smithsonial will not allow anyone to make that kind of inspection. ( They have been asked.) If Oswald's carcano does have the old rifling, it would explain why the last shot began spinning sideways like a whirllygig, blowling a large whole out the side of the President's head before itselt exploding.
We think we are sure that he was using Winchester made ammo in the gun, based on all the evidence. These bullets had a solid core of lead, and copper gilt metal as a jacket. The original Italian ammo, sold here as military surplus, was a steel jacket, with only a small core of lead at the back third of the bullet. The front third was solid steel.
In the Kennedy case, the first shot fired missed the President, and broke up on the concrete curb beyond the limosine. Two spectators receive minor wounds from being hit by bits of that bullet. The curbing is now in the Smithsonian. The second shot struck the President in the back in his shoulder, and is the now Infamous " Magic " bullet, a creation of the media and other ignorant writers, who have never taken the time to actually look at the bullet. The bullet is not pristine, and shows a small dent in the nose of the bullet, and a bend about half way down and flattening toward the base on one side. Part of the lead core is extruding out the base of the bullet, and appears to be the result of the flattening on that one side. The third bullet blew up as it exited the President's head, with two pieces of the lead core being found on the floorboard of the Limo under the driver's feet. One pice hit the inside of his windshield, cracking that insider layer of glass but not the outside layer of glass. The second piece hit a piece of chrome trim above the driver's head, over the sunvisor. One piece weighed about 22 grains, and the other weighs 44 grains.
Tests showed that the two pieces share the same metallurgy as the extruding core of the second bullet. (This is a class characteristic as far as Ballistic's Identification, which just tells us that that lead came from the same batch of metal, like thousands like it.)
The second bullet was ballistically matched to the Oswald gun, as was a bullet taken from the wall of a General Walker's library, after he suffered a sniping attack at his home earlier in the primary campaign. Oswald had confessed and bragged to his wife that he was responsible for that shooting,( Walker was an ultra right- wing conservative candidate supported by Neo- Nazis, and the KKK who ran him in early Democratic Primaries that year). Authorities found newspaper clippings, and other evidence connecting Oswald to that sniping after his death, during the investigation into the deaths of President Kennedy and the Dallas Police officer Oswald also shot.