Heckler & Kock MP5K Briefcase Gun

Officially designated by Heckler & Koch as the ‘Spezialkoffer’ or Special Case, the Briefcase Gun, sometimes referred to as the Operational Briefcase, is a clandestine weapon system designed for personal protection details. The ‘Special Case’ was introduced in the late 1970s offering the firepower of an MP5K in a concealed package which could be rapidly brought into action.

DSC_0678
A view of the case’s exterior (Matthew Moss)

While the MP5K is already a compact weapon that can be carried concealed under a coat or tucked under the arm, the Special Case, in theory, allowed the weapon to be carried in an instantly accessible way. One H&K leaflet stated that the case retains “approximately the same rapid readiness to fire” as an unconcealed submachine gun. The case had the added advantage of being able to be operated with just one hand.

DSC_0681
A view of the case open with MP5K mounted (Matthew Moss)

To build the brief case Heckler & Koch turned to Hofbauer GbmH, a German manufacturer that specialises in extrusion blow moulded protective cases for tools and equipment, to make the case body. The case is made from black plastic moulded over an aluminium body with a stainless steel locking clasps and a strip of silver trim tape around the lower half. Inside on the right hand rim of the lower half of the case is the case maker’s marking ‘Hofbauer Boss Flanegg’.

DSC_0684 - Copy
Close up of the case’s Hofbauer markings (Matthew Moss)

Inside the case Heckler & Koch used a modified STANAG claw mount, with a modified release lever, that was normally used to mount optics on G3s and MP5s. The claw mount system holds the weapon in place and a firing mechanism connects a trigger in the briefcase’s handle to the weapon’s trigger inside. The weapon itself is an MP5K, the example we’re examining today has a ‘SEF’ selector and the contoured stahl G3 griffstück (pistol grip assembly). The MP5K was first introduced in 1976, reportedly developed following a request from the security detail of a South American head of state.

DSC_0673
The case’s HK MP5K (Matthew Moss)

The muzzle of the MP5K’s 4.5 inch barrel fits into a tube or shroud in the left side of the case. Below the weapon is a clip to hold a standard plastic MP5 cleaning kit. While inside the lid of the case there is a clip to hold a spare magazine.  The MP5K-PDW, introduced in the early 1990s, will not fit into the case as the muzzle and folding stock prevents it from fitting.

DSC_0687
A close up of the cases muzzle ‘tube’ and rubber muzzle cap (Matthew Moss)

The trigger in the case’s handle works through a series of linkages which connect it with the MP5K’s trigger. Pulling the external trigger upwards pulls an linkage forward which in turn acts on a pivoted arm which pulls the weapon’s trigger. The case has a built in safety on the left side of its handle. When pulled to the rear with the thumb it moves a blocking bar backwards and allows the trigger, inside the handle, to travel upwards to fire the weapon. There is some variation to the trigger mechanisms with a slightly dog-legged, rather than straight, trigger arm being introduced to allow the use of MP5Ks with ambidextrous selectors.

HK briefcase trigger
The cases’s handle disassembled, showing the trigger mechanism (courtesy of Nicholas Chen)

Once fired the spent cases are deflected down into the body of the case and can only be removed once the case is opened to reload or remove the weapon from the case. There is no ejection system built into the case.

In addition to the case we have examined in this video/article, there is also another version based on a leather satchel-style briefcase, known as the ‘Spezialtasche’ or Special Bag. Instead of the moulded plastic case the MP5K is held inside a leather case with a ‘reach-inside opening’, which allows the user to put their hand inside the case and hold the pistol grip and operate the weapon’s controls. The gun is still held in the same kind of cradle claw mount but the leather case does not have the integrated trigger in its handle. The upper half of the case, held in place by four snap buttons, could come free of the lower section to allow the MP5k to quickly be accessed for reloading and removal from the claw mount.

HK Briefcase and Satchel
Late 1970s H&K product sheet for ‘Spezialkoffer’ or Special Case & leather ‘Spezialtasche’ or Special Bag (source)

As you would expect aiming a briefcase is no easy feat, the Special Case was intended for engaging targets at very close ranges or gaining initial fire superiority, suppressing a target long enough to either deploy the MP5K properly from the case or extricate the principal being protected. One of the major issues with the case is naturally limited access to the weapon which makes changing fire more, clearing stoppages and reloading impossible without opening the case – which can only be accomplished by opening the case’s two locking clasps, which in a contact situation would take precious seconds of fumbling.

Here’s what appears to be some vintage promotional footage showing the case in action:

A substantial number were sold, especially to Middle Eastern countries. During the 2003 Invasion of Iraq, the troops from the US 7th Infantry discovered a cache of 24 H&K Briefcases untouched, like new in their wrappings, bought by Saddam’s regime. Heckler & Koch continue to offer the case, two models are currently listed on their website: the original briefcase, now referred to as ‘Schießkoffer’ or ‘shooting case’, and a quick deploy ‘Zerfallkoffer’ case (offered for both the MP5K and the MP7) .


Specifications (taken from H&K data sheet c.1984):

Case:

Case External Dimensions: 17.24×4.25×12.67in (438x108x322mm)
Weight of case without MP5K: 3.3 lbs (1.5kg)
Weight of case with unloaded MP5K: 7.72lbs (3.5kg)
Weight of case with MP5K + 60 rounds: 14.88 lbs (6.75kg)

Weapon – MP5K:

Length: 12.8in (32.5cm)
Weight (unloaded): 4.4 lbs (2kg)
Barrel Length: 4.5in (11.4cm)
Action: Roller-delayed blowback
Calibre: 9x19mm
Feed: 15 or 30-round magazines
Cyclic Rate: 900 rpm


Bibliography:

Full Circle: A Treatise on Roller Locking, R. Blake Stevens (2006)

The Gray Room, J. Phillips (2010)

‘HK Operational Briefcase: German design, MP5 included’,  Guns.com, C. Eger, (source)

‘H&K MP5K Briefcase: Luggage you can fire’, TFB, R. S., (source)

‘Review: H&K MP5K Briefcase And My Modifications’, TFB, N. Chen, (source)

H&K MP5 brochure c.1985, via Small Arms Review Reference Library (source)

H&K Special Case datasheet c.1979, via Small Arms Review Reference Library (source)

H&K German factory datasheet c. late 1970s for cases, via Small Arms Review Reference Library (source)


Special thanks to the collection that allowed us to examine and film the HK Special Case.