German arms manufacturers have made many fine submachine guns over the years—the country did essentially invent the platform during World War I with the MP18 and refined it to near perfection with the MP40 for use in World War II. There were of course other submachine guns developed in the interwar period including the MP34, MP35 and EMP. Today the Heckler & Koch MP5 remains one of the most widely used submachine guns, as it is carried by police, paramilitary and military forces around the world. However, the H&K had some competition from a rival German arms maker, namely Walther, which released its own compact automatic weapon, actually in two versions the MPK/MPL. The Walther MP series included the Maschinen Pistole Lang (long submachine gun) or MPL; and the Maschinen Pistole Kurz (short submachine gun) or MPK. Both were developed during the late 1950s and introduced in the early 1960s with mass production beginning in 1963. Not surprisingly Walther chambered the weapons for the 9×19-millimeter Parabellum round, which was among the most common submachine gun calibers at the time.

Both versions of the MP were blowback operated, selective fired weapons that fired from an open bolt. The design was unique in that it featured a bolt that was shaped like an inverted “L,” which put most of its mass above the barrel and in front of the breech face. The bolt was also designed to be not captive to the cocking handle, so it would remain in the forward position while the bolt cycled. It fired from a thirty-two-round detachable box magazine and had a rate of fire of five hundred rounds per minute. The MPK had an effective range of about one hundred meters while the MPL was about double that distance.  [full article]