Originally developed as a small anti-torpedo boat gun. During World War I this weapon was mounted on some landing craft and also used as a landing gun. Used during World War II on some small coastal defense boats and submarine chasers.

Gun Characteristics

Designation 6 cm/21 (2.4") Casemate Gun C/98
6 cm/21 (2.4") S-Bts KL/21
6 cm/21 (2.4") Bts KL/21
Ship Class Used On Boat Gun
Date Of Design 1898
Date In Service 1900 (?)
Gun Weight N/A
Gun Length oa 107 in (0.121 m)
Bore Length 99 in (2.505 m)
Rifling Length N/A
Grooves N/A
Lands N/A
Twist N/A
Chamber Volume N/A
Rate Of Fire 12 - 14 rounds per minute


Type Separate
Projectiles and Weight 1 HE L/3,4: 6.0 lbs. (2.71 kg)
Shrapnel: 5.2 lbs. (2.38 kg)
Bursting Charge HE L/3,4: 0.28 lbs. (0.128 kg)
Projectile Length HE L/3,4: 8.0 in (203.2 cm)
Shrapnel: N/A
Propellant Charge 0.25 lbs. (0.115 kg) W.P. 6/07 (4 x 4 x 1.25)
Cartridge 0.96 lbs. (0.435 kg)
60 mm x 64 mm R
Muzzle Velocity HE: 1,434 fps (437 mps)
Shrapnel: 1,470 fps (448 mps)
Working Pressure N/A
Approximate Barrel Life N/A
Ammunition stowage per gun N/A
  • ^From the photographs below, it would appear that other ammunition types were introduced during World War I.


Range with 6.0 lbs. (2.71 kg) HE
Elevation Distance
Range Maximum 3,720 yards (3,400 m)

Mount / Turret Data

Designation Single mounts
Weight N/A
Elevation N/A
Elevation Rate Hand operated, only
Train N/A
Train Rate Hand operated, only
Gun recoil N/A

Additional Pictures


"Naval Weapons of World War Two" by John Campbell
"Munitionslexikon Band2" by Karl R. Pawlas
"Waffenlehre" by Richard Berlin Wille
"Diagrams of Great War - German Naval Guns; Shells & Explosives; Fuses & Exploders" by The Royal Laboratory Woolwich 1921-22
Special help from H. Zertner, Peter Lienau and 1st Sergeant China Ludovic (Belgian Demining Service)

Page History

28 May 2008 Benchmark
19 May 2012 - Updated to latest template
22 April 2016 - Added photographs of gun from early 1900s
08 February 2024 - Converted to HTML 5 format and added shell photographs and sketches