Yeah I mostly have trouble with it on the new WFA maps where the mg 34 can enter a house overlooking the fuel or VP and it's impossible to get him out.
I wouldn't say its impossible. It does require more micro/attention.
assuming you have 1 rifle squad vs 1 MG in a building
also assume that you have unlocked smoke and have the munitions to use it.
you run your Rifle Squad up on the building.
You get quickly suppressed. (not pinned)
you fire a smoke grenade in front of the window the MG is firing from.
the suppression ends and your unit rushes the house, circle strafing it so they can shoot in at it as they circle around it.
you are sure NOT to try and run around the long side of the building so the MG doesn't have time to set up. so you stick to jumping back and forth from 2 sides over and over again. The MG constantly jumping from one window to another to get a shot off at you but never having the time to set up and shoot.
Eventually it dies or they exit the building, or reinforcements arrive (friendly or hostile), either way that is how you use a smoke grenade to take out a MG in a building. I've been doing it with shock Troops for a while now. and trust me the range on the US smoke is soo much better then the Shock Troops that it makes this super easy in comparison.