Heckler & Koch P11

From Wikipedia, the free encyclopedia
HK P11
OS P11
TypeUnderwater Pistol
Place of originGermany
Service history
In service1977–present
Used bysee Users
Production history
ManufacturerHeckler & Koch
Mass1,200 grams (42 oz) loaded
Battery pack 700 grams (25 oz)
Length200 millimetres (7.9 in)
Width60 millimetres (2.4 in)

Cartridge7.62×36mm, about 100 millimetres (3.9 in) long, miniature solid-fuelled rocket with fins
Caliber7.62 mm
ActionElectric actuated
Effective firing range30 metres (98 ft) in air,
10 to 15 metres (33 to 49 ft) underwater
Feed system5 rounds, each in a barrel
Sights14.6 centimetres (5.7 in) between sights

The Heckler & Koch P11 is an underwater firearm developed in 1976 by Heckler & Koch. It is loaded using a pepper-box-like assembly, containing five sealed barrels each containing an electrically-fired projectile. Two styles of barrel assembly can be used: one containing five 7.62×36mm flechette darts for use underwater, or five 133-grain bullets for use above water.[1]


Since ordinary-shaped rounds are inaccurate and have a very short range when used underwater, this pistol fires steel darts underwater or traditional bullets above water.[2][1] It has five barrels, each of which is loaded with a cartridge, giving the gun a pepper-box appearance, and it is electrically ignited from a battery pack in the pistol grip.[3]

Both the underwater dart and above-water bullet barrel assemblies use a sabot to hold the projectile. Each barrel is rifled in two portions: an initial large-diameter designed to spin the sabot and projectile, and a second, narrower section to halt the sabot and spin the projectile.[1] This has two principle benefits: first it reduces the noise produced when the weapon is fire and secondly it reduces exhaust gas released by the weapon that would otherwise cause bubbles.

After firing all five cartridges, the barrel unit must be sent back to its manufacturer for reloading.[4] It is very similar to its predecessor, the Mk 1 Underwater Defense Gun. In the past, Heckler & Koch has denied knowledge of its existence.[5][1]

This firearm is somewhat bulkier than its Soviet counterpart, the SPP-1 underwater pistol, but it has five barrels, as opposed to the Soviet firearm which has four. However, the SPP-1 does not need to be sent back to the manufacturer to be reloaded.


See also[edit]


  1. ^ a b c d McCollum, Ian (1 November 2023). "HK P11: NATO's Secret Underwater Pistol" (video). youtube.com. Forgotten Weapons.
  2. ^ Cawthorne, Nigel (1 March 2012). The Mammoth Book of Inside the Elite Forces. Little, Brown Book Group. p. 220. ISBN 978-1-78033-731-9.
  3. ^ Neville, Leigh (31 March 2016). Guns of Special Forces 2001 – 2015. Pen and Sword. pp. 40–41. ISBN 978-1-4738-8102-0.
  4. ^ Walter, John (2005). Guns Of The Elite Forces. Frontline Books. p. 115. ISBN 978-1-85367-637-6.
  5. ^ Dockery, Kevin (2004). Weapons of the Navy SEALs. New York: Berkley. p. 68. ISBN 0-425-19834-0.
  6. ^ a b c d e f Southby-Tailyour, Ewen (2005). Jane's Special Forces Recognition Guide. New York: Collins. p. 366. ISBN 0-00-718329-1.
  7. ^ "Straight Dope Staff Report: How far can bullets go when fired into water?". The Straight Dope. Archived from the original on 27 March 2008. Retrieved 28 March 2008.
  8. ^ Dan, Alex (9 February 2016). "PASKAL Malaysian Special Forces Weapons". Military Factory (Small Arms). Archived from the original on 14 February 2016. Retrieved 10 February 2016.
  9. ^ "SBS Weapons - HK P11 Underwater Pistol". Elite UK Forces. Retrieved 28 March 2008.


External links[edit]