It all started from these claims:
That create the impression that garrand's long range performance can be ignored because it a "close range" weapon so it does not work with well with LMGs.
It not even the first, the second or even the third time that user has described gareands as "close range weapons".
The claim is simply false (but it seems that some people like to disagree with person that makes a post and not with what it has actually been posted).
It is false in the sense that Garands are not a pure close range weapon in the sense of SMGs, yes.
In what it is true though is that Rifles should close in whenever possible against Volks, Grens and even Obers. That's what the Garand profile dictates them to do. PGrens are the only exception here, but also a rather rare occurrence.
LMG Rifles have a quite odd profile of having no real benefit of closing in between ranges 35 and ~15, but then still have quite a DPS growth below range 15 despite having an LMG.
Some numbers on that:
LMG Rifles deal about 51% of their max damage at range 35, 67% at 15 (+16%) and peak at range 6 with 100%.
For comparison, Grenadiers deal 69% of damage at range 35, 83% at 15 (+14%) and peak at range 0 with 100%.
Combine this with the fact that LMG Rifles and LMG Grens have similar DPS until range ~18, at least against Ostheer it puts Rifles into an odd position.
Staying at far range makes you only trade evenly and is a suboptimal use of your squad (only 51% of max damage, other long range squads deal significantly more).
Closing in from far is not worth it since you gain little DPS in the first place and will even lose your short range models.
Closing in from mid MIGHT be worth it if you don't lose too many of your Garand models.
Staying close is absolutely worth it, but for that you can just buy a BAR.
Against OKW it might look different again, I have not thought it through in detail. Against Volks, I however see that the weird Rifle+LMG profile leads to having better DPS roughly above range 20 and below range 10, in between it is pretty even. So you'll get a better squad, but the behaviour is odd.
But I also did not find the LMGs really worth it in team games. The commander ability technically allows you to skip the rack upgrade, but also this is suboptimal. If you don't buy racks, your rifles still will have a free, unused weapon slot and your echelons stay pretty useless since they can't get zooks.
The upgrade is not super bad on paper, but does not offer that much benefit either. Other weapon upgrades that mix different weapons do it in a way that the whole profile of the squad gets changed, but the LMG upgrade on Rifles doesn't. It creates an odd hybrid.