Why do modern MBTs have smoothbore guns?
As far as I know, smoothbore guns are used to fire HEAT and HE rounds, though they are less effective for indirect artillery fire over long distances; however, they do offer greater barrel longevity. (At least, that’s how I understand it.)
But for HEAT rounds, there are "G-type" shells like those used on the AMX-30, and for APFSDS, it is still possible to fire APDS rounds, which work with rifled guns. That allows for more accurate indirect artillery fire over several kilometers.
That’s my line of reasoning. Of course, if all modern tanks use smoothbore guns, there is surely a reason I haven't considered. I suspect there might be a flaw in my logic, so I’d like to hear your thoughts.