As far as infantry weapon ranges go, a US study from the 1950s or 60s says that for rifles
400 meters covered 97% of engagements or less.
300 meters covered 88% of engagements or less.
200 meters covered 72% of engagements or less.
100meters covered 30% of engagements or less.
We can argue about whose data they used or if the US was biased or if they were trying to make a case for the AR-15 rifle and were biased the other way. I doubt it was going change things by more than a couple of percent.
The problem for using reduced size rifle rounds, and there is quite a good case for doing so, is that the rifles are very often not the deciding infantry weapon of the infantry, especially in WW II. When they looked at machine gun use (and here it is all machineguns) they found that
1600 meters covered 97% of engagements or less.
1200 meters covered 80% of engagements or less.
750 meters covered 50% of engagements or less.
400 meters covered 20% of engagements or less.
Obviously machine guns needed larger, more powerful ammo than rifles, but things are not quite that bad. Lumping all machine gun use together biases the numbers to longer ranges that are used by tripod mounted guns or vehicle guns (tank co-ax machineguns). Trying to use LMGs on bipods at longer than 800 meters is pretty much useless. Bipod mounted guns have a max effective range of 600-800 meters depending on gun, caliber, weight, and how good the bipod actually is or how optimistic the manual writers were.
A bipod mounted machine gun is going to much more effective at 200-300 meters than most troops with rifles and at 4-500 meters is even more marked.
As far as the US and small rifle rounds goes. The US was all in favor of them in the 1960s and 70s, In fact the US and some others tried to go even smaller. Then came dessert Storm and there was a lot of back tracking and scrambling for old weapons in the dusty corners of old depots/arsenals. The US is still arguing about the proper size of the rounds and the proper mix of small rifles to larger rifles and MGs to this day.
Going back to the Italians in the 1930s, the Italians did some things right and some things wrong. Along with everybody else you either use the same round for both rifle and machine guns for simplified logistics or you use two different rounds. The Italians are trying to operate in Libia and Ethiopia for the most part but need to secure the northern border, always against France but against Austria changes with the year. This may affect weapon selection depending on when in the 30s.
The Italians were trying to do things on the cheap (so were a lot of other people) and the ideal rifle for NA was not the ideal rifle for other areas. The Italians apparently thought that changing over from the round nose heavy bullet to a lighter weight spitzer was going to be too expensive. The magazine and chambers in the existing 6.5 Carcano rifles may have had compatibility issues (more jams?) or there was problem with the rifling. In any case somebody thought that boring the exist barrels out to 7.35mm would be cheaper? But they didn't have enough time after 1938 and had to change back (sent the modified guns to 2nd line troops or low threat areas). The 8mm Breda 37 doesn't show up until 1937 and that is 7 years too late to affect the selection of the Breda 30.
I have my doubts about the "Tactical and Technical Trends" entries. Not that are anything different in any way from what you wrote but my doubts are about the writer/s being unbiased and impartial
The Breda light machine gun is similar to the British Bren gun.
really? compared to what? the BAR?
It is mechanically superior to the Bren gun under dusty conditions.
Bren gun does not use an oiler, Bren gun has fewer openings for crap to get inside.
It requires only one man to service it as compared to several for the Bren gun.
And yet the Italian manual calls for a 3 man crew. Granted one man to "use" the gun for short period of time may be different than a "crew".
Trying to use the Brda 30 as a single operator with that reload system pretty much turns it into very poor semiautomatic rifle. Since both guns weighed within about 10% of each other (depending on the MK of the Bren) I fail to see any reason why a single man could not pick the Bren and with 1-2 mags inside his tunic advance a short distance and fire 50-80 rounds until a 2nd man with more mags can join him. Italian manual says the crew carried two spare barrels. British manual says crew carried one spare barrel.
It has a slightly higher rate of fire than the British weapon.
ROFLMAO.
Breda was supposed to fire at 500rpm cyclic. Bren guns were supposed to fire at 480-520rpm depending on exact Mark. Very few guns fired exactly at the book figure anyway, some were faster and some slower. Breda was short recoil operated and maybe there was a way to adjust it. But You tube videos make no mention of adjustments to springs or buffers. Or any buffer at all. Now the real kicker, the Brens were gas operated and the firer could easily select one of 4 gas tracks in the regulator to increase gas flow in dusty/dirty conditions to get the gun back up to speed. Or to increase rate of fire when clean although this was probably frowned on. That said the largest gas track was selected for AA use and get the gun up to 900-1000rpm if needed. A clever feature was that the gas from the gas cylinder was vented to the outside through holes and if the gun started to foul from powder residue twisting the bipod back and forth would usually clear the holes from fouling which is dispersed by the gas from the next shot. Now go back to the bit about the Breda being superior to the Bren in dusty conditions.
Sounds like the US writer for "Tactical and Technical Trends" never fired a Bren gun or fired one very briefly and never bothered to read the manual.
Its disadvantages are that it has no carrying handle, cannot be fired on fixed lines, and has no tripod mounting.
Well, finally, something that sounds right. And 3 things that can be done with the Bren. In fact the Bren can be used on several different tripods/mounts and can be provided with AA sights and can be provided with 100 round drum for AA use. Not often used in practice.
We can go over the Breda 37 later