The Knötgen automatic rifle is a prototype German automatic rifle.
The rifle was designed by Mathias Knötgen of Cologne, Germany; little else is known about the development of this weapon other than that snippet of information, however. It is highly unlikely that this weapon ever advanced past prototype stages, and it is also quite likely that none were actually produced.
The Knötgen was a double-barreled automatic rifle with two barrels stacked above one another, similar to an over-under double-barreled shotgun. The Knötgen operated using what appears to be a lever-delayed blowback mechanism, with a very complex internal system with one lever on a roller to delay the action.
The weapon's detachable box magazines were inserted into the pistol grip, a rarity for any firearm other than pistols at the time. It is not known exactly about how much the magazine held, due to relatively scarce information of the weapon. Other images of the weapon show it to have what appears to be some sort of foregrip up front, mounted underneath the lower barrel.
Probably the oddest thing about the Knötgen was the placement of its charging handle; the Knötgen's charging handle was a lever mounted inline with the stock, which would be pulled out to engage the extremely complicated action to ready the weapon for firing.
A machine gun variant of the Knötgen was also purported to exist, known as the Knötgen Maschinengewehr, which is, quite literally, "Knötgen machine gun". As with its automatic rifle counterpart, it is highly unlikely that it ever advanced past prototype stages. Information about this variant of the Knötgen is even more scarce than that of its automatic rifle counterpart, as no pictures of the weapon or patents of the machine gun variant exist.