I do love the int ops tech levels. I especially like making tech level B vee versions of todays things for the tech B worlds on the fringes in the great houses and periphery, versus tech C stuff on more advanced worlds, and appreciating the difference between them and the full tech D standard combat vehicles.
Infantry tech uses a very different criteria though, so im not sure where we are infantry tech wise.
My TechB militia boys are a ragtag team compared to the tech B tanks, using mortars and sniper rifles and what would be considered vintage Gatling guns, as tech B infantry cant muster a machine gun. Tech B, at least on infantry equipment, is the 'mad max' stuff--makeshift rifles, axes, shotguns and bolt action, ect. While a vehicle machine gun is tech B, infantry machine guns are tech C, which I take as 'RPG balance.'
The logical reasons is cause tech level is very closely tied to the RPG character creation, so all the 'good' stuff is unavailable without 'well equipped' ranks, which also means infantry tech level doesnt follow the rest of battletech's tech level it appears. Cause they dont want an RPG character starting with a machine gun, so they changed the tech codes I assume.