1) An overview of the preceding decades of small arms developments.
2) The Italian small arms situation at the time of the adoption.
3) The larger European state of art, especially of Italy's immediate neighbout powers.
As to No. 1, no other period in small arms development in history has been as rapid and torrent-like as the second half of the 19th century.
It saw the whole change from Ancien Regime to present-day modernity: around 1850, every nation (except Prussia) still used the large smoothbore muzzle-loading musket as main infantry weapon, with all the consequences for warfare and tactics. Then, the first breech-loading conversions began to appear everywhere. Caliber shrank from about 17-18 mms to at first 15 mms and soon to only 10-11 mms. Every look into a cartridge handbook confirms the abundance of new metal-cased cartridges in the 10-11 mms range seeing the light between 1868 and 1886. Almost every nation jumped on the bandwagon, large or small.
Then, beginning with the 1886 introduced smokeless powder French 8 x 50 R Lebel "Balle N", the modern jacketed medium bore cartridges evolved rapidly, in only a few years, most of which are still in use today. The German m/88 cartridge (8 x 57 I) was so genially designed, judging from an interior ballistics viewpoint, (incidentally, NOT by Paul Mauser, but by a military committee), that it still is unsurpassed today for its case-performance effectivity, and has mothered countless military and civilian offspring cartridges (among which the US .30-03, later .30-06).
But the trend went further; smaller and smaller bores were being tested (mostly by Prof. Hebler, in Switzerland), and Italy was the first nation to adopt a *real* smallbore rifle cartridge, though Romania beat it, ultimately, by a few months with introducing also a whole rifle together with a fairly similar cartridge. We may confidently assume that Ferdinand von Mannlicher, the designer of the Romanian M 1892 rifle, had snatched the idea directly from the Italians, who had given him and Mauser a _rimmed_ 6,5 cartridge in order that he might build his entry to the Italian service rifle contest around it. (He did so, but it was rejected - Italy preferred her own designs, which indeed were better.)
As to No. 2, Italy had only recently, in the 1860's, done away with the muzzle-loader (at first, Piemont used Salvatore Carcano's bolt action needle gun conversion of older muzzle-loaders, some features of which bolt would be found applied almost three decades later on the "M 91 Carcano" family...).
In 1870, it was decided to adopt the - at that time - most advanced service rifle design, the Swiss Vetterli rifle for metallic cartridges (!).
Reasonably enough, the Italian army did not stick with the original rimfire design (the USA at this time also had adopted its first military centerfire cartrdige, the.50-70 Govt.), but decided in favour of a (balloon-headed, but massive, not coiled like the British "Boxer" cases) centrefire brass cartridge. Unfortunately, as may think in hindsight, the Italians did not also make use of the Vetterli's second most modern feature, of its tubular magazine. They adopted the M 1870 family (rifle, cavalry carbine, special troops' carbine, carabinieri carbine), but as single-shot loaders. The conservatism of the contemporary, generally prevalent military doctrine had triumphed, for the time being. No waste of valuable and scarce ammo through the undisciplined and licentious soldiery...
After the advent of the improved German M 71/84 and the French M 1886 Lebel magazine rifles, Italy hurried to convert its Vetterlis to a magazine. Again, as hindsight might suggest, over-hastily. Had they but waited a few years, much money would have been saved... so, while Italy did have the merit of being the first nation to introduce the lateron-standard type of the box magazine in the middle of the stock, their design was clumsy, it held only four shots and the old large caliber lead bullet ammo was waiting to be outdated every year by newer developments...
As to No. 3, it was the rapid progress of two of Italy's neighbouring nations which probably prompted the rapid step towards a hyper-modern smallbore rifle. France had adopted in 1886 the sensational Lebel rifle, the first one to use a "smallbore", high-velocity, jacketed bullet, with far longer useful range, and with a large magazine capacity. All the other European nations immediately realized the consequences, were shocked and frightened (especially Germany, in face of France's rampaging war-mongering revanchism linked to the name the unscrupulous, populist and politically over-ambitious General Boulanger) and hurried to step up.
Then came Austria-Hungary and Germany, both of whom had just adopted a 8mm repeating rifle in 1888. Italy now was totally outgunned against her potential enemy, the K.u.K. Empire, and knew it.
Their old M 1870 and M 1870/87 Vetterli(-Vitali)s were no match to the new high-velocity repaeting rifles, even with the possibility of using smokeless powder and a jacketed bullet until a new rifle could be put into service (as an intermediate emergency measure, the Italians adopted a new M 1890 Vetterli cartridge loaded with Nobel's Ballistite - a double-based hot-burning nitroglycerine powder -, which raised muzzle velocity up to 600 m/s).
The Italians ordnance officers who did not wish to be late-comers another time, among them notably Major Benedetti, decided to go the whole way down, and to work with the latest trends and flashy developments, which at this time came from Swiss researchers. They shunned the already-introduced 8mm cartridges and experimented with 6 mm and 6,5 mm barrels, finally adopting a caliber of 6,5 millimeters (the caliber refers to the bore = barrel diameter across the lands), at that time the world's smallest military cartridge.
Now, the caliber question having been preliminarily decided, a weapon for the (not-yet developed) cartridge had to be found...
The time-honoured way to achieve this is to set up a military committee
and let it roam... and so it was done.
President of the commission was General (artillery) Gustavo Parravicino [* 28.3.1837 - + ?] (not Parravicini, as sometimes is written), by virtue of his position as commander of the "Scuola centrale di tiro de fanteria" in Parma; the commission's first secretary was Major Antonio Benedetti, his successor was Colonel Lieutenant Pietro Garelli-Colombo.
Late 1888: after the Austrian adoption of the M 1888 Mannlicher rifle, the Italian Ministry of War incaricates a commission of small arms, attached to the Central Infantery Shooting School in Parma, with the task of studying and proposing a new rifle.
1889: In a first public concurrence, 15 rifles are presented by national and foreign inventors, among them the Italian officers Giuseppe Vitali and Giovanni Bertoldo, as well as Peter Paul Mauser and James Paris Lee.
16.-17.12.1889: The commission rejects all proposed models.
17.-18.4.1890: Upon recommendation of Major Benedetti (based on extensive tests conducted in the Brescian state factory, probably in March), the commission decides to go away from the previously tested 8 mm and 7,5 mm cartridges and to use 6,5 mm as the new rifle caliber.
Following months of 1890: Another 10 models are submitted.
In the meantime, Col.Lt. Pietro Garelli-Colombo has succeeded Maj. Antonio Benedetti in the crucial position of Secretary. Being faced with the problems of severe and rapid throat erosion as well as of lacerated bullet jackets, he decides (probably after comparative tests having been conducted in August 1890) to adopt progressive rifling. As supplier of barrel steel (barrel blanks), the Poldihütte in Kladno near Prague is chosen.
Major Vitali's suggestion of an all-brass bullet (such as lateron the French would adopt as "Balle D") is rejected in favour of a maillechort-plated jacketed bullet with lead core.
23.9.1890: Since none of the submitted models so far has satisfied the
commission, the four Italian state factories/ government arsenals (of
Brescia, Terni, Torino, Torre Annunziata) are formally charged with
studying and presenting additional rifle models.
Mauser and Mannlicher, still in business, are given constant-twist barrels (as to keep the secret of the progressive twist to Italy) and a newly-developed 6,5 mm rimmed cartridge upon which they have to build their rifles.
Another 45 models of foreign and Italian inventors are rejected; the commission concentrates now on the improvement of the models submitted by the state factories.
23.4.1891: The commission decides to combine an Italian state factory
rifle model made by the Torino factory with the German Mod. 1888
charger-loaded central magazine of Mannlicher origin and to pay Ferdinand
Ritter von Mannlicher the appropriate royalties of a flat fee of 300,000
Lire. The adopted and reworked magazine is netly superior to
Mannlicher's original model, as already was the German version.
Salvatore Carcano [1827-1903], "capotecnico principale" of the Torino arsenal, is the person who is responsible both for the model and for its rework employing the commission-approved magazine. This authorship is why the rifle will lateron be named in his honour.
One thousand prototype rifles of the modello uno (Torino) and the competing modello due (jointly made by Terni and Torre Annunziata) are distributed to troops for trials. The troops report in favour of Mod. 1.
The "Laboratorio Pirotechnico di Bologna", which parallel to the rifle developments works on the new cartridge, comes forth with an important change: and the commission makes an extremely modern decision. They skip the commonly used rim (which would be found in the adopted military cartridges of France, Russia, Austria, United Kingdon, USA, Romania, Netherlands, Denmark, Japan) and present an ultra-modern rimless cartridge with an extractor groove (probably influenced by the genial German m/88 cartridge), the later 6,5 x 52 mm. The two rifle models are thus renamed to Mod. 1 bis and Mod 2 bis, to denote the change to the new round.
August 1891: changes to the sights lead to a last modification: Mod. 1 ter.
31.12.1891: last term for the presentation of the new rifle model.
4.-5.3.1892: The Commission decides in favour of the Torino rifle modello 1 ter (designed under the direction of Salvatore Carcano) as Italy's new small arm, and calls it "Modello 1891".
29.3.1892: The Ministry of War follows the decision of the commission and formally adopts the rifle with its Act No. 57.
9.6.1893: A cavalry carbine is presented by the commission.
15.7.1893: The Minsitry of War adopts the cavalry carbine with the Act No. 116.
23.8.1893: A special "guard cartridge" (basically, a shrapnel load) is adopted.
February 1896: the propellant of the cartridges is changed from the hot (double-based, nitroglycerine) original Ballistite of Alfred Nobel to the less erosive, colder nitrocellulose Solenite. The new cartridge is called M 91/95. Ballistite will remain in use for special loads (blanks e.g.)
End of 1897: A carbine for special troops is adopted (the Moschetto TS),