And you only have an mg, that is not supported by other units? Ah so no tech grenades are "free" now? Great, then shock trooper grenades are free too? Good!
If you thought about it for just one second, you might have found out that the "free grenades" was meant as "no tech". I assume that was too much to ask from you. Better start trolling new forum members and then make lopsided comparisons. Great stuff mate. I'll remind you of that next time you complain about the CoH2 player base being too small.
Seriously, how do you beat this as USF? They tear up rifles, they run straight through HMGs, they get free grenades. I can't see a way to beat a half competent Ost player that uses them.
Alright, on a serious note:
I've also had problems as USF against this tactic. not sure what the best thing to do is. AA Halftrack maybe if you make it that far probably. Haven't tried an early BAR upgrade yet, could be a decent idea as well.
Mortar or other indirect won't help you much. MGs only in small corridors. And I think you mostly have to ignore the CQC parts of the map until the mid game. USF is a tough one against Assault Grenadiere, but maybe the balancing of the next patch might change a bit here.