HIW VSK
The Hessische Selbstladekarabiner also known as HIW VSK  refers to 2 prototype weapons, a rifle and a carbine, of German origin developed by Hessische Industrie Werke and August Cöenders in 1944. They were intended as Volkssturm weapons and the carbine variant used blow forward operation. Variants

Battle rifle
Chambered for the 7.92×57mm Mauser rifle round. It used standard 5-round stripper clips to fill the fixed internal magazine. To operate, the "bolt" handle is actually attached to the barrel, and pushed forward to feed a new round to a fixed bolt and breech face. Carbine
Chambered for the 7.92×33mm Kurz round. It used special 5-round stripper clips to fill the fixed internal magazine. The barrel is blown forward by drag of the bullet and propellant gasses and returns under spring pressure, chambering a new cartridge. References

7.92×57mm Mauser battle rifles
Blow forward firearms
Carbines
Research and development in Nazi Germany
Rifles of Germany
World War II infantry weapons of Germany

Weapons and ammunition introduced in 1944