Heckler & Koch HK MP5 The HK MP5 is a German submachine gun created by Heckler & Koch and used by many amies and special forces around the world . It is the standard submachine major special operations units in the world ( SWAT , BOPE , GOE , GSG9 , etc . . . ) . Description . The Heckler und Koch submachine gun , MP - 5 , is one of the most famous and widespread firearms of its class , developed since the Second World War . Its development began circa 1964 under the company designation HK MP - 54 , or simply HK 54 . In the 1966 , German police and Border Guard adopted the HK 54 as the MP - 5 , and it was originally available in two forms - MP - 5 with fixed buttstock and MP - 5A1 with retractable buttstock . Some years later HK slightly upgraded the design of MP - 5 , replacing the sights ( from flip - up open notch rear and blade front to drum - type diopter rear and hooded post front ) and the muzzle ( replacing the two - slot muzzle compensator to the tree - lugs QD silencer mount without compensator ) . Other improvements made over the time concerned the magazines ( early type magazines were of straight box type , latter - of curved box type for improved reliability ) . The trigger units also were upgraded - from original stamped steel with plastic grip to the all - plastic units , integral with grip , and with various fire modes and marking . Over the years MP - 5 were adopted by the huge numbers of police , security and military forces around the world , including the German police and border guard , British police and elite Army SAS units , American police , FBI , U . S Navy and U . S Marine Corps , and many , many others . MP - 5 is still manufactured in Germany by the HK itself , and also licensed to Greece , Iran , Pakistan and Mexico . The only real rival to the MP - 5 in the terms of proliferation across the world is the famous Israeli UZI submachine gun . Most interestingly , the German Army ( Bundeswehr ) did not adopted the MP - 5 , most probably due to the economical reasons , and turned instead to the . . . UZI submachine guns , made under license in Belgium . The success of the MP - 5 is outstanding . It is based on the high quality and reliability of the gun , great single - shot accuracy ( thanks to its closed bolt action ) , great flexibility and , of cause , good marketing . It seems that no other modern SMG at this time can rival the MP - 5 in popularity ( UZI is not manufactured anymore ) . The MP - 5 , basically , is no more than the scaled - down version of the Heckler - Koch G3 battle rifle . It shares the same basic design with stamped steel receiver and the same roller - delayed blowback action , derived from the post - war CETME rifles . The trigger units are hinged to the receiver and are now available with various fire mode options , including 2 ( Safe , Semi - auto ) , 3 ( Safe , Semi , Full Auto ) or 4 ( Safe , Semi , Limited burst of 2 or 3 rounds , Full auto ) position levers , ambidextrous or not , and marked with letters , digits or icons . The MP - 5 is always fired from closed bolt for improved accuracy , but this limits the amount of sustained fire due to the barrel overheating and resulting cook - off problems . To avoid this , MP - 5 cocking handle could be locked in the rear position in the special slot , leaving the bolt in the open position , with no cartridge in the chamber . To commence the fire one must simply release the cocking handle from its notch and then pull the trigger . Modern MP - 5 submachine guns are equipped with three - lug quick detachable silencer mounts on the barrel . Sights are similar to other HK models , and consists of the front hooded post sight and the adjustable for windage and elevation drum - type diopter rear sight . Special quick - detachable clamp mounts allows for installation of night , optical and red - dot sights if required . Standard magazine capacity is 30 rounds , but shorter 15 rounds magazines are available . Special versions were developed and manufactured in limited numbers during 1980s - 90s for the US Law Enforcement market , chambered for more powerful 10mm Auto ( 10x25mm ) and . 40S & W ( 10x22mm ) ammunition . These guns can be easily distinguished from more common 9mm models by straight box 30 rounds magazines , made from plastic . While all of MP - 5 can be fitted with silencers , there also a dedicated silenced version of MP - 5 , called MP5SD2 or SD3 ( depending on the stock type ) . This version is equipped with non detachable integral silencer , and the vented barrel , to reduce the bullet muzzle velocity down below the speed of sound . The MP - 5SD is intended to fire standard 9mm ammunition , not the special subsonic one . Semi - automatic only versions of the MP - 5 were once made for civilian market under the designation of HK - 94 , some with longer , 16 inch ( 406 mm ) barrels , to conform with US laws . There also is an US company , called Special Weapons LLC , that is manufacturing semi - automatic , civilian MP - 5 clones in various pistol calibers , including the . 45ACP .