[Griefbringer]

With tanks, it is in my experience to engage MG bunkers from the front, if you do not need to be particularly concerned about their return fire.

For the infantry to take out a bunker from the front with small arms fire is not particularly recommendable, since it is likely to require massive amounts of shooting and the return fire is likely to be deadly. So it is preferable to pop smokes and try to sneak up into a flanking position for close assault. Clever opponents (and scenario designers) probably try to make such outflanking manoeuvers difficult by clever placing of minefields and supporting bunkers with overlapping fields of fire.