|conventional weapons require different ammunition for diferent roles. heres an idea.
standard round: 500joule apds. small penetrator inside sabot.
at low velocity the sabot doesnt seperate and acts as an outer casing for the penetrator within.
in the rifle variant the longer barrel raises the velocity to the point where the sabot will seperate- giving longer range
potentially a current could be passed thru the gas- ETC raising velocity further.
finally in the emplaced variant, the barrel is that of a railgun, the armature for this is the combustion gas,etc
a whole suite of weapons using the same ammo.. good idea?