The King Tiger?s 88mm main gun has a muzzle velocity of 1000m per second when firing armor piercing rounds. It was highly accurate and able to penetrate 150mm of armor at distances exceeding 2200m. Since the flight time of an armor piercing round at a range of 2200m is about 2.2 seconds or less, accuracy and correction of fire against moving targets is more important than with older anti tank guns. This made this heavy predator ideally suited to open terrain where it could engage enemy tanks at long range before the opponent?s weapons were even in range.
Krupp had designed the turrets to fit both the Porsche and Henschel chassis. The initial design called P-2 Turm (or commonly known as Porsche turret) mounted a single piece (monobloc) barrel of the 88mm and had a curved mantlet in the front. The front armor was 100 mm thick, the sides were 88mm thick sloped at 60 degrees and the top armor was 40mm thick. It had space to carry 16 rounds of ammunition in the turret. However, the curved mantlet in the front acted as a shot trap by deflecting incoming shots downwards towards the roof of the hull. A new design was ordered to fix this but as an interim measure, it was decided to go ahead with the production of 50 units with this turret. This was commonly referred to as Porsche turret. The new design called Serien Turm, or commonly known as Henschel or Production turret was to retain the many features of the Porsche turret and was to be adopted for mass production. Henschel turret had the front curved mantlet replaced with one 180mm thick armor plate sloped at 81 degrees. The sides were altered to slope at 69 degrees and it could carry an additional 6 six rounds or 22 rounds of ammunition in the turret. The full combat weight was 68,500kg when fitted with the Porsche turret and 69,800kg with the Henschel turret.
Armor (mm/angle) Front Side Rear Top/Bottom
Porsche turret 100/curved 80/30 80/30 40/77 40/90
Henschel turret 180/9 80/21 80/21 40/78 40/90
Superstructure 150/50 80/25 N/A 40/90 40/90
Hull 100/50 80/0 80/0 40- 25/90
Some intresting info here.
http://www.worldwar2aces.com/