12-02-2014, 05:04 AM
(This post was last modified: 05-03-2014, 07:19 PM by Bob Prudhomme.)
Early carbine versions of the M91 long rifle, plus the M91/24 TS carbine (manufactured from 1924-1928 until the introduction of the M91/28 carbines) were simply cut down versions of the M91 long rifles. The 31 inch long rifle barrel was cut back to 17 inches and often machined to a narrower diameter so as not to look out of proportion.
While being an economical method of producing a carbine, it was a disaster as far as making an accurate shooting carbine went. The M91 long rifles were machined with "progressive" or "gain" twist rifling, unlike the far more common "standard" twist rifling. The M91 was made with 1:19 twist at the breech (meaning that the riflings made one full turn in 19 inches) which grew progressively tighter going down the barrel; ending up with a fast 1:8 twist at the muzzle. As the 162 grain Carcano bullet is somewhat heavy for this calibre, a 1:8 twist is essential for giving the bullet enough spin to stabilize it in flight and give it any accuracy.
Unfortunately, cutting off 14 inches of a 31 inch progressive twist rifle barrel removes the part of the barrel with the tightest twist, and destroys any hope that rifle had of being accurate.
In 1938, the Italians made sweeping, long overdue changes to the concept of their basic infantry weapon which, until this point, had been the M91 long rifle. Disappointment with it among the troops, plus the anemic bullet it fired, led the Italian authorities to scrap both the long rifle and the 6.5x52mm cartridge. Among the long rifle's deficiencies was the fact it was too long and too heavy to make it a practical weapon for an army that was relying increasingly on motorized transport. This is a trend that continued on in the 20th Century and gave us compact weapons such as the M1 Carbine, the Kalashnikov AK-47 and the Armalite AR-15 (better known in the military as the M-16). The only advantages of having a long rifle, such as the M91 with its 31 inch barrel, were that the longer barrel gave the bullets a higher muzzle velocity, and thereby a higher ballistic coefficient, and the longer rifle gave the soldier extra reach during bayonet charges. However, since bayonet charges were practically obsolete, following the introduction of the medium machine guns in WW I, and war makers found the majority of combat to be taking place at ranges under 100 yards, these advantages were seen as something that could be sacrificed.
The other deficiency in the 6.5mm Carcano long rifle was the bullet fired from that weapon; the 6.5x52mm cartridge loaded with a full metal jacket, round nosed, flat based 162 grain bullet. Quite simply put, this bullet was not very good at killing people. Compared to many other bullets, this bullet was very long and narrow, lending it great stability in flight and in a wound. Instead of tumbling or expanding in a wound, these bullets often punched straight through to the other side of their victim, doing very little damage. While adhering strictly to the humanitarian conventions of the 1899 Hague Peace Conference, these bullets were a curse to the soldiers in the field, as it was seldom possible to stop an enemy combatant with one shot.
For these reasons, it was decided, in 1938, to introduce an all new "short" rifle (neither long rifle or carbine) with an all new calibre plus a new design of bullet that would overcome the "humanitarian" issues. While the 7.35x51mm calibre was new, everything about the rifle (receiver, bolt, magazine and feed system) was identical in every respect to the 6.5mm M91 long rifle. Even the cartridges were identical, outside of the case length being 1 mm shorter. In fact, it is possible to make a 7.35 mm brass cartridge simply by taking a 6.5mm Carcano casing and resizing the neck of the case with a 7.35 resizing die, as well as trimming the case length slightly.
The most significant feature of the new 7.35mm bullet was that, inside the jacket of the bullet, instead of being 100% lead, only the back end of the bullet was lead. The forward half (or third, actually) of the bullet, inside the jacket, was made from the very light metal aluminum. This created an imbalance in mass in the bullet from front to back, and actually caused these bullets to tumble once in a wound, causing great and grievous injuries. This was further enhanced by discarding the 6.5mm's round nosed bullet and giving the 7.35 a pointed bullet. While new to Italian troops, this bullet was actually a slavish copy of the British .303 Mk. VII cartridge introduced in 1907, in response to the banning of the British .303 Mk. II "Specials" (dum dum bullets) and the Mk. IV and V cartridges (hollow point bullets) at the Hague Peace Conference. This information should be studied carefully by students of the JFK assassination, as it still defies belief that a 6.5mm FMJ Carcano bullet could have done what is claimed at z313.
Another important thing to understand, perhaps THE most important thing, is that it was not necessary to change the calibre of the Carcano just to adopt a pointed, aluminum tipped bullet. It would have been far simpler to just make this new bullet in 6.5mm calibre. The real reason for making the new 7.35mm rifles had more to do with Italy's limited steel making capacities.
The 7.35x51mm M38 short rifle was going to be part of the ultimate recycling program. From the First World War and their African campaigns, Italy had great inventories of 6.5mm M91 long rifles, many with worn out barrels. As the plan, in 1938, was, for all eternity, to abandon the long rifle AND the 6.5mm calibre, these rifles were viewed as surplus. The choice of a new calibre in excess of 7 mm (the 7.35) was no coincidence, either. The plan was, until their vast stocks of M91 long rifles ran out, to cut the long rifle barrels from their length of 31 inches to the new short rifle length of 21 inches and make this shortened barrel the foundation of a new short rifle. The shortened barrel would then be drilled to a new bore diameter of 7.35 mm, completely eliminating the rifling grooves of the 6.5mm calibre and, essentially, making a new barrel. As the old bore was 6.5 mm, and the old groove diameter was 6.8 mm, drilling the new bore diameter of 7.35 put the lands of the new bore .275 mm further into fresh barrel metal than the bottoms of the old grooves.
The obvious question is, why not just cut the long rifle barrels to a new length of 21 inches and keep the 6.5mm calibre, and save having to drill them out to 7.35mm? The answer is simple and we can go back to the start of this thread where the making of carbines from long rifles is discussed. The 162 grain 6.5 mm bullet required a fast rifling twist of 1:8 to stabilize it in flight. The M91 long rifle was made with "progressive twist" rifling, meaning that the rifling started at 1:19 at the chamber, where the bullet began its journey, and progressively got tighter; achieving the final rifling of 1:8 at the muzzle of the barrel. At the end of a 21 inch cut off barrel, the rifling would be nowhere near tight enough to stabilize the 6.5mm bullet, and accuracy would suffer dramatically.
This was a perfectly sound idea, one that would have given the Italians a fine weapon with good stopping power. While its barrel was 10 inches shorter than the M91 long rifle, it was no longer required to shoot the heavy 162 grain 6.5mm bullet. The 7.35mm bullet, despite being larger in diameter, weighed only 128 grains, due to the light aluminum nose and there simply being less metal in a pointed bullet, as compared to a round nosed bullet. This combination, coupled with a 1:10 standard twist rifling, gave the 7.35mm an impressive muzzle velocity of just under 2500 feet/ second, almost 100 fps faster than the M91 long rifle. In comparison, firing the heavy 6.5 mm bullet through the 6.5mm carbines and short rifles only gave muzzle velocities of 2000 and 2200 fps. Not only this, the lighter weight of the 7.35mm bullet and its pointed nose gave it a higher ballistic coefficient, causing it to retain more of this velocity and performance down range.
More to come.......
While being an economical method of producing a carbine, it was a disaster as far as making an accurate shooting carbine went. The M91 long rifles were machined with "progressive" or "gain" twist rifling, unlike the far more common "standard" twist rifling. The M91 was made with 1:19 twist at the breech (meaning that the riflings made one full turn in 19 inches) which grew progressively tighter going down the barrel; ending up with a fast 1:8 twist at the muzzle. As the 162 grain Carcano bullet is somewhat heavy for this calibre, a 1:8 twist is essential for giving the bullet enough spin to stabilize it in flight and give it any accuracy.
Unfortunately, cutting off 14 inches of a 31 inch progressive twist rifle barrel removes the part of the barrel with the tightest twist, and destroys any hope that rifle had of being accurate.
In 1938, the Italians made sweeping, long overdue changes to the concept of their basic infantry weapon which, until this point, had been the M91 long rifle. Disappointment with it among the troops, plus the anemic bullet it fired, led the Italian authorities to scrap both the long rifle and the 6.5x52mm cartridge. Among the long rifle's deficiencies was the fact it was too long and too heavy to make it a practical weapon for an army that was relying increasingly on motorized transport. This is a trend that continued on in the 20th Century and gave us compact weapons such as the M1 Carbine, the Kalashnikov AK-47 and the Armalite AR-15 (better known in the military as the M-16). The only advantages of having a long rifle, such as the M91 with its 31 inch barrel, were that the longer barrel gave the bullets a higher muzzle velocity, and thereby a higher ballistic coefficient, and the longer rifle gave the soldier extra reach during bayonet charges. However, since bayonet charges were practically obsolete, following the introduction of the medium machine guns in WW I, and war makers found the majority of combat to be taking place at ranges under 100 yards, these advantages were seen as something that could be sacrificed.
The other deficiency in the 6.5mm Carcano long rifle was the bullet fired from that weapon; the 6.5x52mm cartridge loaded with a full metal jacket, round nosed, flat based 162 grain bullet. Quite simply put, this bullet was not very good at killing people. Compared to many other bullets, this bullet was very long and narrow, lending it great stability in flight and in a wound. Instead of tumbling or expanding in a wound, these bullets often punched straight through to the other side of their victim, doing very little damage. While adhering strictly to the humanitarian conventions of the 1899 Hague Peace Conference, these bullets were a curse to the soldiers in the field, as it was seldom possible to stop an enemy combatant with one shot.
For these reasons, it was decided, in 1938, to introduce an all new "short" rifle (neither long rifle or carbine) with an all new calibre plus a new design of bullet that would overcome the "humanitarian" issues. While the 7.35x51mm calibre was new, everything about the rifle (receiver, bolt, magazine and feed system) was identical in every respect to the 6.5mm M91 long rifle. Even the cartridges were identical, outside of the case length being 1 mm shorter. In fact, it is possible to make a 7.35 mm brass cartridge simply by taking a 6.5mm Carcano casing and resizing the neck of the case with a 7.35 resizing die, as well as trimming the case length slightly.
The most significant feature of the new 7.35mm bullet was that, inside the jacket of the bullet, instead of being 100% lead, only the back end of the bullet was lead. The forward half (or third, actually) of the bullet, inside the jacket, was made from the very light metal aluminum. This created an imbalance in mass in the bullet from front to back, and actually caused these bullets to tumble once in a wound, causing great and grievous injuries. This was further enhanced by discarding the 6.5mm's round nosed bullet and giving the 7.35 a pointed bullet. While new to Italian troops, this bullet was actually a slavish copy of the British .303 Mk. VII cartridge introduced in 1907, in response to the banning of the British .303 Mk. II "Specials" (dum dum bullets) and the Mk. IV and V cartridges (hollow point bullets) at the Hague Peace Conference. This information should be studied carefully by students of the JFK assassination, as it still defies belief that a 6.5mm FMJ Carcano bullet could have done what is claimed at z313.
Another important thing to understand, perhaps THE most important thing, is that it was not necessary to change the calibre of the Carcano just to adopt a pointed, aluminum tipped bullet. It would have been far simpler to just make this new bullet in 6.5mm calibre. The real reason for making the new 7.35mm rifles had more to do with Italy's limited steel making capacities.
The 7.35x51mm M38 short rifle was going to be part of the ultimate recycling program. From the First World War and their African campaigns, Italy had great inventories of 6.5mm M91 long rifles, many with worn out barrels. As the plan, in 1938, was, for all eternity, to abandon the long rifle AND the 6.5mm calibre, these rifles were viewed as surplus. The choice of a new calibre in excess of 7 mm (the 7.35) was no coincidence, either. The plan was, until their vast stocks of M91 long rifles ran out, to cut the long rifle barrels from their length of 31 inches to the new short rifle length of 21 inches and make this shortened barrel the foundation of a new short rifle. The shortened barrel would then be drilled to a new bore diameter of 7.35 mm, completely eliminating the rifling grooves of the 6.5mm calibre and, essentially, making a new barrel. As the old bore was 6.5 mm, and the old groove diameter was 6.8 mm, drilling the new bore diameter of 7.35 put the lands of the new bore .275 mm further into fresh barrel metal than the bottoms of the old grooves.
The obvious question is, why not just cut the long rifle barrels to a new length of 21 inches and keep the 6.5mm calibre, and save having to drill them out to 7.35mm? The answer is simple and we can go back to the start of this thread where the making of carbines from long rifles is discussed. The 162 grain 6.5 mm bullet required a fast rifling twist of 1:8 to stabilize it in flight. The M91 long rifle was made with "progressive twist" rifling, meaning that the rifling started at 1:19 at the chamber, where the bullet began its journey, and progressively got tighter; achieving the final rifling of 1:8 at the muzzle of the barrel. At the end of a 21 inch cut off barrel, the rifling would be nowhere near tight enough to stabilize the 6.5mm bullet, and accuracy would suffer dramatically.
This was a perfectly sound idea, one that would have given the Italians a fine weapon with good stopping power. While its barrel was 10 inches shorter than the M91 long rifle, it was no longer required to shoot the heavy 162 grain 6.5mm bullet. The 7.35mm bullet, despite being larger in diameter, weighed only 128 grains, due to the light aluminum nose and there simply being less metal in a pointed bullet, as compared to a round nosed bullet. This combination, coupled with a 1:10 standard twist rifling, gave the 7.35mm an impressive muzzle velocity of just under 2500 feet/ second, almost 100 fps faster than the M91 long rifle. In comparison, firing the heavy 6.5 mm bullet through the 6.5mm carbines and short rifles only gave muzzle velocities of 2000 and 2200 fps. Not only this, the lighter weight of the 7.35mm bullet and its pointed nose gave it a higher ballistic coefficient, causing it to retain more of this velocity and performance down range.
More to come.......
Mr. HILL. The right rear portion of his head was missing. It was lying in the rear seat of the car. His brain was exposed. There was blood and bits of brain all over the entire rear portion of the car. Mrs. Kennedy was completely covered with blood. There was so much blood you could not tell if there had been any other wound or not, except for the one large gaping wound in the right rear portion of the head.
Warren Commission testimony of Secret Service Agent Clinton J. Hill, 1964
Warren Commission testimony of Secret Service Agent Clinton J. Hill, 1964