The Standschütze Hellriegel 1915 is a water-cooled submachine gun produced in very limited numbers for the Austro-Hungarian reserves (Standschütze) during World War I, by a designer identified only as "Hellriegel". A highly obscure weapon, no complete examples are known to still exist, and little official documentation remains. As a result, its operating mechanisms, exact production numbers and development history are all based on speculation. However, photographic evidence exists of it in live-fire tests which are dated October 1915, making it one of the earliest submachine gun designs in history.
The weapon could be fed from either box magazines or chute-fed. Contrary to its in-game depiction, the drum magazine developed for the Hellriegel could not be attached to the weapon itself; it was designed to be carried by another soldier. It is unknown why the weapon did not progress beyond the prototype stage.
— In-game description
A Hellriegel 1915 Storm variant, equipped with a Buckhorn Sight, assumedly reduced recoil and increased zoom, can also be found in a crate in the War Story, Through Mud and Blood.
— In-game description
The Hellriegel 1915 Factory is unlocked upon reaching rank 10 with the Assault kit. The weapon's high magazine capacity of 60 rounds makes it extremely effective against enemies in close quarters compared to other submachine guns and LMGs. Despite this, its relatively moderate recoil makes it somewhat difficult to engage enemies at longer ranges unless controlled shots are fired. It also overheats after 40 bullets straight.
The Hellriegel comes equipped with 180 rounds of ammunition (60 rounds loaded in the magazine and 120 carried in reserve).
— In-game Description
The Hellriegel 1915 Defensive is a weapon variant introduced in the Spring Patch. It is unlocked upon completion of the correlating assignment which involves obtaining 300 kills with the Factory variant and 25 kills with Anti-Tank Mines. Unlike the default variant, it features a Bipod, an Extended Magazine holding 120 rounds and a Lens Sight. Consequently, it features much higher recoil.
- A glitch in the class ranking system allowed players to purchase the weapon before being level ten in the Assault class. This was due to the system incorrectly tracking values higher than what was intended. This was fixed in a patch but allowed players to keep the weapon if already purchased, even if the rank 10 criteria had not been met.
- The Hellriegel used to have only 120 rounds (translating to 60 loaded and 60 rounds carried in reserve), but after the Spring Patch, it was buffed to have 180 rounds instead to give it a higher advantage (translating to 60 rounds loaded and 120 rounds carried in reserve).
- A faint water sloshing sound can be heard while moving with the Hellriegel. This presumably comes from its water-cooled barrel.