If you disagree still, what existing indigenous platform do you propose would be the best for a belt-fed MG42 equivalent?
Ask your self in the MG 42 was really that good of a solution to the problem/s The Italians (or many other people) faced. This is heresy to a lot of people
The High rate of fire sounds like a cool Idea, but it needs a crap load of ammo, the gun fires more bullets but it also misses the target more. It needs more spare barrels. It needs more men to carry the ammo.
The MG was a 2nd generation GP machine gun, that is
General Purpose machine gun. It was supposed to do
everything. Squad machine gun on bipod, company (battalion) machine gun on tripod, AA machinegun on different tripod ( or same one folded up by an origami master). AA machine gun on multiple dedicated mount. AFV machine gun. It was better at somethings than others. The 1200rpm firing rate was real good for AA work, it wasn't so good for a lot of other roles. If you
had the manufacturing faculties (the ability to to make a stamped sheet metal receiver) it was cheap to make. The stamping machinery was not cheap. You are trying to make a high cycle rate full powered belt feed machine gun. Manufacturing techniques that work on a 9mm submachine gun don't work anymore.
Italy was already producing the Big Breda 37 machine gun for the army in the company/battalion role and the AFV role. It seemed to do fairly well in those roles. Not ideal but it was generally considered to be reliable which goes a long way with infantrymen. They will put up with heavy, slow firing and even strange (idiotic) feed systems if the gun will fire when they need it to fire. Germans and just about everybody else was moving to heavier guns for AA work pretty quick during the war, assuming the factory capacity to do so.
Belt feed light machine guns look a lot cooler in movies than in real life. Dragging belts through dirt, sand, foliage and other "stuff" usually leads to jams/stoppages with Mr Murphy sitting in a camp stool nearby. Which means there were all sorts drums, boxes, bags and sleeves showing up to hold the ammo as the guns moved (Germans usually unloaded the gun or only left a short belt exposed with moving)Practical Rate of fire of a bipod mounted machinegun is usually down around 120-150rpm due to cooling issues rather than feed issues or actual cycle rate of the gun mechanism.
Italians used the MG 42 (MG 3)for quite a while after WW II, they also came up with a different bolt that would lower the cycle rate to 900rpm. There was also a spring plunger that could reversed and lower spring action also lowered the firing rate. One recommendation for the MG 42 when firing at a rate of 225-250 round per minute (trigger held back for about 20% of the time) was to change the barrel after firing three 50 round belts. Think about that one
Start with cold barrel, fire at 225-250 rounds per minute and change barrels twice in the first 2 minutes. At the end of 3 minutes you have fired off every belt the squad was carrying for the gunner.
MG 42s work a lot better when the gunners are riding in APCs or trucks.