The Apostle tank's primary design purpose is to be used as a glorified MBT, since it is much heavier and larger. the Apostle tank is about 85 tons with ammunition.
It is equipped with 2x dual barrel 50. cal remote turrets, 1x 182mm barrel and one 7.62mm rotary cannon as the coaxial secondary. The rounds used in the Apostle are longer than normal, about 1.5 meters in length which allows for a greater range and penetration ability with DU KE rounds. An advanced automated reloading system allows for a quick reloading time, approximately 14 shots per minute, faster than any MBT to date. The Apostle is also capable of removing its extended barrel for CQC situations, letting its canister rounds and rotary cannon do most of the work.
The armor is a maximum of 70in. in the front and in the thinnest areas about 35in. the armor composition is respectively from outside to inside (frontal armor), 20mm tungsten+5in. of space (not included in total armor thickness), 40in. of liquidmetal (not liquid, research it), 5in. of MCN (multiwalled carbon nanotubes), 4in. of Vectran which doesn't vary in thickness throughout the whole tank (again, look it up, it's primary function is as a nuclear resistant material), and lastly 1in. of titanium as the internal plating. the armor is rated to be entirely impenetrable on the sides and front with a direct hit from a 120mm rounds. 120mm heat rounds are capable of making it 10in. through the tungsten plating in the front. It's full armor potential is classified but operators have reported direct hits from mobile gun systems at close range with little effect.
An important part of the design in the HCV was its nuclear surviveability. Tests show that it remains mobile after a hit approximately 5 miles from a 100kt nuclear detonation, and 2 miles from the point of detonation the crew would be protected from thermal and radiation effects assuming the blast force doesn't cause damage to the operators (e.g. a flying building doesnt fall on the tank or the wind blast doesn't throw it hundreds of feet in the air). after 7 miles from the point of detonation there is no significant damage to the tank from a 100kt nuclear bomb.
The HCV was the most effective vehicle deployed in combat to date. it finally forced weapons designers to start thinking outside the box, which is where the Standard Articulation Unit project came into play three decades later.
Excuse the poor quality image, i probably should have let it finish anti-alias.