Maschinenpistole Senn
Waffenfabrik Bern (W+F Bern) · Submachine Gun · Prototype · 1916
Also known as: MP Senn, Senn Automatic Luger, Full-Auto Parabellum (Senn)
Overview
The Maschinenpistole Senn is an experimental Swiss selective-fire machine pistol developed during the First World War, built by converting the toggle-locked Parabellum (Luger) service pistol chambered in 7.65x21mm Parabellum to fire fully automatically. Designed by Heinrich Senn of Bern in 1916, it used a sloped trigger sear that let the reciprocating toggle breechblock pass over it uninterrupted while the trigger was held down, catching the block only on release, thereby giving both single shots and continuous fire. A machine-carbine version fitted with a shoulder stock and a barrel jacket was reportedly intended for aircrew. It was trialled by the Swiss Army but never adopted.
Specifications
| Action Type | Short Recoil |
| Firing Mechanism | Striker Fired |
| Trigger Type | Single Action |
| Magazine Capacity | 8 rounds |
| Magazine Type | Detachable Box |
| Muzzle Velocity | 370 m/s (1214 fps) |
| Muzzle Energy | 412 J (304 ft·lbf) |
| Effective Range | 50 m (55 yd) |
| Barrel Rifling | Right Hand |
| Rifling Twist | 250 mm (9.84") |
| Number of Grooves | 4 |
| Frame Material | Steel |
| Barrel Material | Steel |
| Finish | Blued |
Calibers
- 7.65x21mm Parabellum · primary — also known as .30 Luger, 7.65mm Luger, 7.65mm Parabellum
Features
- Firing modes: Semi Automatic, Full Automatic
- Feed systems: Detachable Box Magazine
- Safety mechanisms: Grip Safety, Manual Safety
- Features: Toggle Action, Selective Fire, Converted Luger Pistol
Service history
Operators
- Swiss Army (trials)
Conflicts
- World War I (1914-1918)
Production
Production years: 1916-1917
Experimental prototype only; never mass-produced or adopted by any military.
Origin
Country of origin: Switzerland
Designer: Heinrich Senn
Notes
Full-auto conversion of the Swiss Ordnance Luger. Physical dimensions of the surviving pattern are not reliably documented; the caliber, weight and barrel figures reflect the base Parabellum service pistol on which it was built. A sample was sent to Germany for evaluation in 1917, paralleling Georg Luger's own automatic-pistol experiments.
Background
Heinrich Senn patented his automatic Luger mechanism (German patent DE310499) in 1916, and a sample was shipped to Germany in 1917 - closely mirroring Georg Luger's own contemporary full-auto Parabellum experiments that helped push German thinking toward the machine pistol.