briefly.
The first model was the 1891 Carcano rifle, its 30.8” barrel adapted for a knife bayonet. Next came the M1891 Carcano carbine with a folding bayonet permanently attached to its 17.5” barrel, and the M1891 TS carbine with a 17.5”-plus barrel and detachable knife bayonet. There was also the Model 41 rifle with a 27” barrel. All of these were made only in 6.5mm caliber.
In 1938 Italy adopted a new cartridge of larger caliber—the 7.35mm Carcano. It was based on the same case as the 6.5mm Carcano cartridge but with the neck expanded to hold the larger 7.35mm bullet. The rifles chambered for this cartridge were the M38 short rifle with a 21.1” barrel and detachable bayonet, and the M38 carbine with a 17.5”-plus barrel. Italy, however, soon became involved in WW II and could not make a complete change-over to the new caliber, so it was dropped in favor of the older 6.5mm. As a result, many M38 rifles and carbines made for the 7.35mm cartridge were rebarreled for the 6.5mm load.
W.H.B. Smith, in his The Book of Rifles says that some M38 rifles were made in 7.92mm caliber (8x57mm Mauser) for use by Germany during WW II.
The 6.5mm Carcano rifle barrels were made with progressive or gain twist rifling; that is, the rate of twist gradually increasing from breech to muzzle. At the breech the twist was about one turn in 19”, increasing to about one turn in 8” at the muzzle.
The 7.35mm Carcano barrels were made with a uniform rate of twist, one turn in 10”.
The Carcano Action
The Carcano is a relatively simple turnbolt, 6-shot repeating action having some Mauser and Mannlicher features, plus others found only in this action. Despite wide criticism leveled against it, the Carcano is a well designed and rugged action for military use since, presumably, the Italians did not have any major trouble with it or they would have changed the design.
The Carcano receiver appears to have started as a forging which was then milled and machined to final dimensions. The round receiver ring is quite large in diameter (1.335”), with only a small projection underneath to form the recoil shoulder. The inside of the receiver ring, threaded to receive the barrel shank, has a thin collar left in its center against which the breech end of the barrel abuts. The barrel breech is flat except for a thin ring which fits inside the receiver collar and around the head of the bolt, The rear of the receiver ring is milled to form locking recesses for the bolt lugs. There is more than ample metal at this point to securely support both locking lugs. In the lower left side, in the locking lug recess, a shelf of metal is retained which has a forward sloping surface. The angle of this surface matches a beveled corner on the left (upper) locking lug; on opening the bolt this arrangement provides the initial extraction camming power; on closing the bolt rapidly it helps to start the closing rotation of the bolt. The receiver walls behind the receiver ring are smaller in diameter than the ring; on the left side of the receiver there is a definite step, as in the large ring 98 Mauser action.
The left receiver wall is much higher than the right, and the high left wall lacks a thumb notch. A long opening is milled in the bottom of the receiver for the magazine. The rear half of this opening is wide enough to accept the cartridge clip, while the front half is only slightly wider than the body of the cartridge. The front end of this opening is sloped toward the chamber to form a loading ramp to raise and guide the cartridge from the magazine to the chamber. Cartridge feeding into the chamber is positive and reliable.
The receiver bridge is split or slotted at the top to allow passage of the bolt handle. The receiver ends in a top tang about 2.5” long.
The trigger mechanism is mounted below the receiver bridge and tang. The sear attaches to the receiver, pivoting on a pin crosswise through a hole in the bottom of the bridge. A projection (made separately, but more or less permanently pinned in place) on the rear of the sear projects upward through a hole in the tang into a groove which is milled out for the sear notch to engage the cocking piece when the bolt is closed. The sear is tensioned by a coil spring positioned between recessed holes in the front of the sear and receiver. The trigger, attached to the sear, pivots on a pin through the sear. The upper part of the trigger, which bears against the bottom of the receiver, has twin humps which produce the two stage pull.
The ejector is a collared pin positioned over and inside the sear spring and extending upward through a hole in the receiver. A long tapering groove is cut into the front half of the bolt body to allow the ejector to rise, as the bolt is opened, to contact the head of the cartridge or case and eject it from the action. This appears to be a very efficient, though simple, arrangement.
Italian Model 91 Mannlicher-Carcano action (shown with loaded clip in place).
The bolt-stop is equally as efficient and simple as the ejector. It is a bar extending upward through a hole in the bottom right side of the receiver which projects into the right locking lug raceway in the receiver bridge. The bolt-stop is attached to an arm on the trigger. Pulling the trigger back moves the bolt-stop down so the bolt can be removed.
The bolt and bolt handle appear to have been machined from a one-piece forging, although the latter may have been permanently attached to the bolt by other means. The bolt handle is near the center of the bolt and, when the action is closed and locked, the heavy rectangular base of the bolt handle is forward of the receiver bridge, acting as a safety lug should the forward locking lugs fail. The shank of the bolt handle, round and quite thin, ends in a round grasping ball. On the Carcano rifles the bolt handle sticks straight out, but is bent down on the carbine.
The dual-opposed front locking lugs are quite large and solid; neither has any slots or holes. The bolt face is recessed for the cartridge rim, but the rim of the recess is cut away one-fourth of its diameter for the extractor hook. Another quarter is cut away beyond the bottom of the extractor hook to allow the cartridge head to slip under the extractor hook when fed into the chamber from the magazine. This prevents double loading.
The one-piece spring steel extractor, about 2” long, is mortised into the front of the bolt. A projection under the front end of the extractor fits in a slot in the bolt, preventing the extractor from pulling out. Cartridges normally slip under the extractor hook when being chambered from the magazine. Closing the bolt on a cartridge that is chambered ahead of the extractor (as in single loading the rifle by dropping a cartridge into the chamber) is difficult because the extractor hook is not made to slip easily over the cartridge rim.
The major parts of the firing mechanism are the firing pin, coil mainspring, firing pin nut, cocking piece and bolt sleeve. In addition, there is a spring and plunger in the cocking piece, the purpose of which is to prevent the firing pin nut from turning. The mainspring is compressed between a shoulder on the one-piece firing pin and the bolt sleeve which is backed by the cocking piece. All are retained on the firing pin by the firing pin nut, which threads on the rear of the firing pin. A flat spot on the firing pin matching a similar spot in the cocking piece prevents either part from turning on the other. A shoulder at the rear end of the firing pin prevents longitudinal movement of the firing pin in the cocking piece when the firing pin nut is fully tightened.
The bolt sleeve is usually defined as that part of the action which holds the firing mechanism in the bolt. In the Carcano action the bolt sleeve does this, but it also performs the function of a safety. A small lug on the front part of the bolt sleeve slides into a groove and notch cut into the rear of the bolt body. When the action is cocked, the bolt sleeve is held forward by the lug engaging the notch, and heavy mainspring pressure holds it in this notch so that it rotates with the bolt. When the bolt is closed and the bolt handle down (it must be in this position or the rifle cannot be fired) part of the flange on the rear of the bolt sleeve is also engaged in a notch cut into the receiver tang. This keeps the bolt sleeve in place, and there is little chance of it
