Carcano got the job for producing a NEW Rifle with a better calibre , what happened? They where not able to produce this gun in the numbers required and so the Italian soldiers used the some weapon as there fathers in the war before, with the same deficiencies.
Er, Carcano died in 1903
Carcano designed only the bolt system (IIRC) of the "original" 1891 rifle. The rifle itself was designed by a commission and had a somewhat complex development (the bullet was designed first, then changed to rimless while the rifle design was underway). For some reason in English the name stuck with the whole rifle, but in Italian the rifle is just called by its commission year (i.e., "il 91").
What happened was that the '91 turned out to be an extremely sturdy rifle, so after WWI there were a lot of still more-or-less functional surplus rifles laying around. So instead of making a completely new (and modern) design from scratch (*), it was thought to modernize the existing rifles. Thus the Carcano 38 (or 91/38, depends on the naming style used) inherited most peculiarities of a 1890 design...
BTW, it's doubtful the 38 would have been a better rifle than the 91 - Finnish experience with it was negative for example. Certainly it was an interesting experiment (
very short barrel (**), fixed sights only, what would nowadays be called an intermediate cartridge), but it would probably have added new defects too.
(*): actually a semiauto rifle was being developed at the same time (the 91/38 was somewhat of a stopgap measure) and was even used in limited numbers, but like most semiauto models of the time it was too complex to mass produce (not to mention field maintenance)
(**): note that it's supposed to be a full battle rifle, not a carbine as FH2 says)
About the production system: main problem was that budget and political issues prevented importing or licensing foreign models. As a result, with rare exceptions almost everything fielded by Italy had to take into heavy consideration what could actually be entirely produced indigenously.
So, the Breda 30 LMG was selected over the czech ZB vz.26 (which then became the Bren, type 96, etc.etc.) because they had to get a license for it.
FIAT owned pretty much the only factories in Italy able to produce tanks, so there wasn't much choice as to who to award the contracts. BTW, the L6/40 (which FH2 calls "FIAT L6/40" IIRC) was developed by Ansaldo as an export model (with a much more conventional turret!), and only produced by FIAT because Ansaldo didn't have the capability to mass-produce it.
FWIW, the opposite happened for plane production: there were too many (private) design teams, and during the '30s the government tried to keep them all busy... with the result of fielding a huge number of different designs (which all shared underpowered radial engines).
Bomber design focused almost exclusively on trimotori (3-engined) simply because italian-designed radial engines were not reliable enough to use a two-engine layout.
Radial engines also influenced the late 30s and early war trend of highly maneouvrable but really slow fighters. Later high performance Italian planes were povered by a Daimler-Benz licensed engine that Alfa Romeo had privately bought the license for (i.e., the military didn't finance it).
More or less the same happened with plane MGs, the original ones were underpowered, so they just switched to german models.
Due to this in hindsight Italy (apart from maybe France) would have been the country which would have gained the most by American lend lease equipment. That's not so hypothetical as it sounds nowadays, as until mid-1939 (signing of the Pact of Steel) the side Italy would take in the clearly approaching conflict between Germany and France-Britain wasn't actually defined (pre-war plans and preparations for a war against Germany were never shelved and kept being updated even during the WW2 btw)