with what faction hm?
in general you just get some mg's, face them the right way, and some support infantry with an AT gun and siege it.
Or wait until hes fighting elsewere and try to take it out quick when his forces are diverted.
early game all allied factions have mortars of some type if you cant shoot it directly with an AT gun.
and late game all allied factions have rocket arty that can clear the area around these hqs and punish placing it so close to the front really easily.
in addition to offmaps. Plenty of ways. So many ways im having trouble naming them all.
