I wonder. Once body armor that can readily stop all current individual weapons becomes commonplace, what's next?
It's the endless cycle of armor vs. armament.
Unarmored extremeties are still vulnerable to conventional firearms. Class III helmets and faceplates aren't anywhere on the horizon, so the failure drill will still have a place in weapons implementation.
Before gunpowder and the longbow, ancient knights were still vulnerable to daggers through the faceplate and armor joints. Blunt trauma, like a mace, could still ring an armored knight's bell.
Ammo design will catch up with the new armors. Once class III and IV starts to proliferate to our nation's enemies, a paradyne shift will occur with weaponry. New micronized AP/HEDP projectiles (I think explosive small arms bullets are against the Hauge Convention, for now), directed energy weapons, sonic weapons, or something else from the next wave.
Maybe a miniaturized 15 or 20mm HEDP warhead in a Heavy Support Rifle is just what the doctor ordered. Something M-14 sized or slightly larger, for knocking out armored individuals or light armored vehicles. The XM-109 is a step in the right direction, but the Barrett platform is too bulky to haul around, in my opinion, and it only has a 5 round capacity. Minimum 10 rounds per mag in the Heavy Support Rifle.
Just thinking off the top of my head.
Best,
John Bear Ross