Heckler & Koch P11

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]

HK P11
OS P11
Type	Underwater Pistol
Place of origin	Germany
Service history
In service	1977–present
Used by	see Users
Production history
Designed	1970s
Manufacturer	Heckler & Koch
Produced	1976
Specifications
Mass	1,200 grams (42 oz) loaded Battery pack 700 grams (25 oz)
Length	200 millimetres (7.9 in)
Width	60 millimetres (2.4 in)
Cartridge	7.62×36mm, about 100 millimetres (3.9 in) long, miniature solid-fuelled rocket with fins
Caliber	7.62 mm
Action	Electric actuated
Effective firing range	30 metres (98 ft) in air, 10 to 15 metres (33 to 49 ft) underwater
Feed system	5 rounds, each in a barrel
Sights	14.6 centimetres (5.7 in) between sights

Design

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 principal benefits: first, it reduces the noise produced when the weapon is fired and second 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.

Users

•  Denmark^[6]
•  France^[6]
•  Germany: German commando frogmen.^[7]
•  Israel^[6]
•  Italy: Italian Navy COMSUBIN.^[6]
•  Malaysia: Pasukan Khas Laut (PASKAL) of the Royal Malaysian Navy^[8]
•  Netherlands^[6]
•  Norway^[6]
•  United Kingdom: Special Boat Service of the British Royal Navy.^[9]

See also

• SPP-1 underwater pistol – Soviet four-barreled underwater dart pistol
• Underwater firearm – Firearms that can be effectively fired underwater
• Electronic firing – Type of firearm action

Notes

1. 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. 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.

References

• Dockery, Kevin (2004). Weapons of the Navy SEALs. New York: Berkley. ISBN 0-425-19834-0.
• Southby-Tailyour, Ewen (2005). Jane's Special Forces Recognition Guide. New York: Collins. ISBN 0-00-718329-1.

External links

• HKPRO: The HK P11
• Securityarms: Heckler & Koch P11 Underwater Pistol
• Modern Firearms: Heckler Koch HK P11 underwater pistol
• HK P11: NATO's Secret Underwater Pistol