Deleted member 1487
I see it as the dominance of automatic weapons in general, which in WW2, given the lack of an assault rifle for most armies (the Soviets effectively had a proto-version with their PPSH companies), meant that they had to rely on some version of an MG or auto-rifle to give them the necessary weight of fire.Thats correct as far as they go. What I take away from those is the capability of that weapons mix limited the company/battalions weapons area of influence. Second, looking at the numbers its argument for increasing the number of LMG. Your MG are influencing the battlefield at a average range of 400-500 meters, the Garands only out to 300. Later the use of full volume or automatic fires from the M16 reduced the rifle squads influence to under 300 meters. When we returned training for other battlefields in the 1970s a effective squad range of 250 meters was ok for a assault but inadequate. It was also clear that even with a bipod the M16 and M14 were not worth much as a platoon or squad automatic weapon. They were too light for sustained fire & like the BAR magazine capacity reduces volume significantly.
Theoretically platoon level MGs were firing out to 500m, but squad level ones, such that they existed, were mostly 300m or less because the rate of hits even at that range was low, hence the switch to small caliber, high velocity weapons with a theoretical range of 500m, but a more practical one out to 300m. Even then the US added the M60 into squads for Vietnam, but already in the mid-'60s saw that they needed something like the M249 instead, which combat in Vietnam confirmed.
As to training post-Vietnam, that was largely theoretical based on assumptions from Middle East fighting, and ideas about what the Soviets would be capable of; the WW2 situation was something altogether different due to lack of body army, lack of scopes for the average rifleman (which is a large part of range limitations on infantry; you can't hit or suppress what you cannot see), the impact of less mechanization for European armies compared to the 1970s, the impact of large numbers of conscripts with limited marksmanship training, etc. Plus ITTL we are talking about a 7.92 intermediate cartridge rather than a 5.56, which had greater effective range (going by German reports it was effective in single shot out to 400m for the average rifleman).
All I'm talking about for the OP TL is that the use of a somewhat less advanced LMG and one grouped differently in a weapons squad at the platoon level rather than in the squad as it's base of fire. Given the use of bolt action rifles, maybe an SMG, and perhaps a magazine fed LMG in most Allied rifle squads through at least 1943, an assault rifle only squad (besides the rifle grenadier) backed by a platoon level LMG squad would dominate at normal WW2 combat ranges.
Perhaps that might have had something to do with not having access to Army level of artillery fire support?A lot more than the Army infantry company, they went through the war with nine BAR & two MMG in the company. A couple more MMG could be typically seconded from the battalion MG group. The Armored Infatry Company had a lot more MG, roughly ten - twelve or one per vehicle in the company.
In WWII the Marines doctrine/equipment mix was driven more from the bottom up, vs the top down dominance imposed by Army Ground Forces. In part this was because of the large number of 1942 veterans rotated to support units back in the US, in part because of the much higher portion of combat veterans among the USMC officers prewar, & in part because the colonels at battalio, regiment, and the division/corps staff were given more responsibility or flexibility in arming the rifle battalions.
Mechanized infantry is a different situation altogether than a comparable foot infantry unit in any military.