Pistol · Obsolete / Non-standard
4mm Übungsmunition
German WWII indoor training cartridge fired through a sub-caliber insert installed directly inside a standard service pistol.
- Caliber
- 0.1791″ · 4.55 mm
- Introduced
- 1940
- Case
- Rimless
- Primary use
- Training
- Status
- Obsolete
- Introduced
- 1940
- Type
- Pistol
- Origin
- Germany
- Inventor
- German Ordnance Department
- Manufacturer
- German State Arsenal
- Standard
- Obsolete / Non-standard
- Status
- Obsolete
- Availability
- Collector Only
- Case capacity
- 1.2 gr H₂O
- Primer
- Small Pistol
- Case type
- Rimless
- Max pressure
- 12,000 psi
- Eff. range
- 25 yd
- Max range
- 30 yd
- Recoil
- 0.1–0.3 ft·lb
- Subsonic
- Capable
Ballistics
Published velocity/energy data isn't available for 4mm Übungsmunition — an obsolete/collector cartridge.
Performance
Dimensionscase measurements · scale drawing · size vs familiar rounds
Case dimensions — the scale drawing at the top of the page is built from these.
mixed/other · approximate| Measure | mm | in | ✓ |
|---|---|---|---|
| Bullet ⌀ | 4.55 | 0.179 | ~ |
| Neck ⌀ | 4.86 | 0.191 | · |
| Shoulder ⌀ | 5.52 | 0.217 | ~ |
| Shoulder angle | 14.2° | — | ~ |
| Base ⌀ | 5.52 | 0.217 | · |
| Rim ⌀ | 5.66 | 0.223 | · |
| Belt ⌀ | n/a | ||
| Rim thickness | — | — | |
| Neck length | 2.80 | 0.110 | ≈ |
| Case length | 6.60 | 0.260 | ~ |
| Overall length | 9.08 | 0.357 | · |
Size vs familiar rounds
Drawn at true 1:1 — every case is accurate relative to the others. Absolute size depends on your screen's pixel density, so measuring one against a real ruler may be off. 4mm Übungsmunition is highlighted below.
Factory loads
Being verified
Advertised FPS, energy, and BC are withheld until loads clear verification.
Reloading costestimate cost per round vs factory
Estimate your cost per round and how it compares to factory. Inputs are yours — nothing is stored.
Cost estimate only — not load data. Charge weight is your input; follow published manuals for safe charges.
Connected reference
History
The Wehrmacht faced a training ammunition shortage as WWII progressed — live 9mm Parabellum was too valuable to burn on stationary target practice, and dedicated training ranges were being destroyed by Allied bombing. German ordnance engineers developed a steel insert that fit inside the barrel and chamber of the standard Walther P38 and Luger P08, reducing the bore to 4mm. Soldiers loaded the insert, chambered a 4mm cartridge, and fired — experiencing the actual trigger, grip, and sights of their service weapon. The tiny 4mm projectile had just enough energy to penetrate a paper target at 10-15 meters. The system was later adapted for rifles and submachine guns. It represents one of the most ingenious training ammunition solutions ever devised: zero retraining on a different weapon, zero cost of a separate training pistol, and usable in any bombed-out basement.
FAQs
- What bullet diameter is 4mm Übungsmunition?
- 4mm Übungsmunition uses a 0.1791″ (4.55 mm) diameter bullet.
- Is 4mm Übungsmunition still in production?
- 4mm Übungsmunition is obsolete; typical availability is collector only.
- What is 4mm Übungsmunition used for?
- 4mm Übungsmunition is primarily used for training.
Sources & provenance
Data & sources. Specs compiled from the Lindcott Armory reference; availability counted from 5 live factory loads; the trajectory is modeled (point-mass), not measured. See methodology. Spotted an error? Report it →