Heckler & Koch MP5 - Variants

Variants

MP5A2 has a fixed stock (made of a synthetic polymer), whereas the compact MP5A3 has a retractable metal stock.

In the early 1970s HK introduced a conversion kit for the MP5 that enables it to use sporting ammunition (.22 LR). This unit consists of a barrel insert, a bolt group and two 20-round magazines. This modification reduces the cyclic rate to 650 rounds/min.

The MP5A2 and MP5A3 are available with optional four-position trigger groups; these are known as the MP5A4 and MP5A5 respectively. The trigger groups are marked with bullet pictograms rather than letters or numbers (each symbol represents the number of bullets that will be fired when the trigger is pulled and held rearward with a full magazine inserted in the weapon) and are fully ambidextrous (the selector lever is present on each side of the trigger housing). The additional setting of the fire selector, one place before the fully automatic setting, enables a two or three-shot burst firing mode.

The modular design of the MP5 offers multiple trigger groups: three-position "SEF" fire selector (positions: "S"-safe, "E"-semi automatic, "F" fully automatic. Located on left of receiver only); three-position fire selector (positions: safe, semiautomatic and a 2- or 3-round burst; selector lever is ambidextrous and its settings are marked with pictograms); four-position fire selector (positions: weapon safe, single fire, 2- or 3-round burst, full auto; ambidextrous selector; selector settings marked with pictograms); two-position fire control group (positions: weapon safe, single fire only; ambidextrous selector lever with pictograms) and a three-position fire selector group—the so-called “Navy” trigger (settings: weapon safe, semi-automatic, fully automatic fire; ambidextrous selector lever; selector settings marked with bullet symbols again).

A variant with the last trigger group designated the MP5-N (N—Navy) was developed in 1986 for the United States Navy. This model has a collapsible stock, a tritium-illuminated front sight post and a 225 mm (8.9 in) threaded barrel for use with a stainless steel sound suppressor made by Knight's Armament Company together with quieter subsonic ammunition.