Wimmersperg Spz-kr
Heinrich Freiherr von Wimmersperg · Rifle · Prototype · 1944
Also known as: Spz-kr, Wimmersperg Spz
Overview
The Wimmersperg Spz-kr was an experimental German bullpup assault rifle designed in 1944-1945 by Heinrich Freiherr von Wimmersperg as a low-cost, easily-manufactured alternative to the StG 44 during the final phase of World War II. It combined stamped-steel construction and components salvaged from the British Sten Mk II submachine gun (receiver and buttstock) with the StG 44's 30-round magazine, magazine release, and barrel blanks, chambered in the 7.92x33mm Kurz intermediate cartridge. The gas-operated, selective-fire design used a progressive trigger, in which a half pull fired single shots and a full pull produced sustained fire, and the magazine itself formed the pistol grip. No complete prototypes are known to have been built before the war ended.
Specifications
| Overall Length | 680 mm (26.77") |
| Action Type | Gas Operated |
| Firing Mechanism | Hammer Fired |
| Trigger Type | Progressive |
| Magazine Capacity | 30 rounds |
| Magazine Type | Detachable Box |
| Muzzle Velocity | 685 m/s (2247 fps) |
| Muzzle Energy | 1900 J (1401 ft·lbf) |
| Effective Range | 300 m (328 yd) |
| Barrel Rifling | Right Hand |
| Frame Material | Stamped Steel |
| Barrel Material | Steel |
| Stock Material | Steel |
| Finish | Phosphate |
Calibers
- 7.92x33mm Kurz · primary — also known as 7.9 PP Kurz, 8mm Kurz, 7.92mm Kurz
Features
- Firing modes: Semi Automatic, Full Automatic
- Feed systems: Detachable Box Magazine
- Features: Bullpup Layout, Swappable Barrel, Selective Fire, Progressive Trigger, Magazine Forms Pistol Grip
Service history
Conflicts
- World War II (1939-1945)
Production
Production years: 1944-1945
Never mass-produced; no completed prototype is confirmed to survive
Origin
Country of origin: Germany
Designer: Heinrich Freiherr von Wimmersperg
Discontinued: 1945
Notes
The 'Spz-kr' designation stands for 'kurze Bauart mit Regler' (short pattern with regulator/burst switch). The design is known only from surviving blueprints and post-war reconstructions; no original wartime example is confirmed to have been completed.
Background
Conceived as a 'last-ditch' Volkssturm-era weapon, the Spz-kr aimed to marry the cheap stamped tooling of the Sten to the German intermediate cartridge, foreshadowing post-war bullpup assault rifles decades before they became mainstream.