The increasing size of the Mark XV led to a fresh attempt at specialized design, and the Mark XVI was, in effect, a 'light' Mark XV. Main armament remained a 50cm Hellbore, but the infinite repeater batteries were reduced to a total of eight weapons and the howitzer armament was deleted. (As partial compensation, the Mark XVI replaced its laser infinite repeaters with ion-bolt projectors, with much greater ability to penetrate ablative armor, and received a six-gun battery of short-range breech-loading 20cm mortars to augment its anti-personnel clusters.) A complete ablative outer hull was adopted to replace previous appliqués, and cybernetics were equivalent to those of Mark XV/R . Weight fell to 3,600 tons, and road speed rose to 90 kph with short duration "sprints" of up to 100 kph poss