The Humanitarian Rifle

[Bob Prudhomme]

Now that we have established the primary reason the 6.5mm Carcano was dubbed the "Humanitarian Rifle", that being the terminal ballistics of the 6.5x52 mm cartridge were insufficient to give the rifle serious stopping or killing power, let us see if we can find other reasons for this nickname.

As I stated in the last post, the M91 6.5mm Carcano long rifle was not an inaccurate weapon; its only fault was that it fired a very long, stable, round nosed, full metal jacket bullet that adhered strictly to the conventions of the Hague Peace Conference. It was designed to cause limited damage in a wound and it did everything its designers intended.



Above, M91 long rifle

As in most armies, the M91 long rifle, with its 31 inch barrel, was issued to the infantry. Other branches of the army, such as cavalry, artillery, scouts and support troops also needed weapons but it was found early on that such a long unwieldy weapon as the M91 did not work well in these applications. Something shorter was needed and the "carbine" rifle was developed. Two carbine models were introduced in the 1890's, the Moschetto da Cavalleria (cavalry carbine) and the Moschetto per Truppe Speciali (special troops or TS for short).



Above, cavalry carbine with permanently attached and folded back bayonet



Above, special troops or TS carbine

The 6.5 Carcano M91 long rifle was made with what is known as "progressive" or "gain" twist rifling grooves, as opposed to the far more common "standard" twist rifling grooves. While standard twist rifling has the same rate of twist throughout the length of the barrel (for example 1:7, meaning the riflings make one complete turn in 7 inches of barrel length), the M91 riflings started, at the breech, at a gentle 1:19 twist, and progressively got tighter, achieving a twist rate of 1:8 at the muzzle where the bullet exited. As the Carcano bullet was relatively heavy for its calibre at 162 grains, it was necessary to have the fast 1:8 rifling twist to gyroscopically stabilize the bullet in flight and give it accuracy. Without this fast twist, the bullet is under stabilized and accuracy suffers dramatically.

The cavalry carbine was the first to be introduced in 1893 and was made, quite literally, by sawing the front half of an M91 barrel off, reducing its length from 31 inches to 17 inches. The M91 wooden forestock was cut short, as well, the bolt handle turned down from the M91 straight bolt handle and the rear sight changed. It is not known how much of the progressive twist rifling was sacrificed but it is likely safe to say what remained of the barrel had, at most, a rifling twist of only 1:13. As many modern shooters have discovered, this short sighted and very stupid error on the part of the Italian authorities caused the Moschetto da Cavalleria to be a carbine that "couldn't hit the water from a boat". Early production of the TS carbine, beginning in 1897, also were made from cut down M91 long rifles.

Following WW I, Italy was left with great inventories of M91 long rifles and a stagnating economy. In a move to modernize their army with shorter weapons not as unwieldy as the M91's and to keep production costs down, the M91/24 TS carbine was introduced in 1924, again with a 17 inch barrel. M91 long rifles were cut down again to make the M91/24 TS, and this new version of the TS carbine was to become the main service rifle until the lead up to WW II in 1938. Once again, no thought was given to the disastrous effects removing 14 inches of a 31 inch progressive twist barrel would have on the accuracy of that rifle. OTOH, it was likely the progressive twist rifling that was the inspiration for the M91/24 TS in the first place. As the gentle 1:19 rifling at the breech of the M91 barrel would cause far less barrel wear than the 1:8 rifling at the muzzle, a "worn out" M91 barrel could be made new simply by removing the worn out forward 14 inches of the barrel and making it into a carbine.



Above, M91/24 carbine. It should be noted that the rifle in the Klein's ad would appear to be an M91/24 although it looks a bit wrong in the area of the bayonet mount.



Above, M91/28 carbine

The only relief to this carbine madness was the introduction in 1928 of the M91/28 TS carbine. It was an all new rifle and not a cut down version of a long rifle. Its introduction ended the manufacture of M91/24's. Perhaps someone came to their senses and realized what inadequate weapons were being supplied to Italian troops. Regardless, many of the M91/24's were made and saw great service in WW II and likely contributed to the poor performance of the Italians in North Africa.

So, we have now seen another reason the Italian troops dubbed the 6.5 Carcano the "Humanitarian Rifle". Careful note should also be made of the Italians' propensity for recycling worn out or overstocked M91 long rifles, with no regard for the detrimental effects on rifle accuracy of removing the tightest part of the progressive twist rifling. This will be discussed again in the next installment of the "Humanitarian Rifle", in which I will discuss the real reasons the 7.35x51 mm M38 Carcano was discontinued.