Complex sentence: These are essentially HEAT rounds effective against older tanks and other armored vehicles but with improved fragmentation, blast and fuzing to have a reasonable anti-personnel/materiel effect so that they can be used in place of conventional high explosive rounds against infantry and other battlefield targets.
Split into simpler sentences: These are essentially HEAT rounds which are effective against older tanks and other armored vehicles, but have improved fragmentation, blast and fuzing. This gives the projectiles an overall reasonable light armor and anti-personnel/materiel effect so that they can be used in place of conventional high explosive rounds against infantry and other battlefield targets.