Wikipedia
Kampfwagenkanone
Kampfwagenkanone (KwK) ( tank gun) — meant for use in a fully rotating turreted mount on any Panzerkampfwagen-designation armored fighting vehicle of Germany in World War II — may refer to any of the following guns used by the German Wehrmacht's armored forces during the war.
Also see anti-tank guns and anti-aircraft guns.
Name
Barrel length
Tank gun used on
2 cm KwK 30
L/55
110 cm
2 cm KwK 38
PzKpfw II
3.7 cm KwK 36
L/45
166.5 cm
5 cm KwK 38
L/42
210 cm
5 cm KwK 39
L/60
300 cm
7.5 cm KwK 37
L/24
176.65 cm
7.5 cm KwK 40
L/43
347.3 cm
L/48
385.5 cm
PzKpfw IV, Ausf. G-J
7.5 cm KwK 42
L/70
525 cm
8.8 cm KwK 36
L/56
492.8 cm
8.8 cm KwK 43
L/71
628 cm
12.8 cm KwK 44
L/55
704 cm