Autocannon · Military · Not SAAMI standardized · Not standardizedObsolete
20mm Hispano
The 20×110mm cartridge of the Hispano-Suiza HS.404 aircraft autocannon, the standard 20 mm gun of British and American fighters in the second half of WWII.
- Caliber
- 0.7874″ · 20 mm
- Introduced
- 1938
- Case
- Rimless
- Primary use
- Military
- Status
- Obsolete
- Obsolete
- Obsolete
- Introduced
- 1938
- Type
- Autocannon
- Origin
- Switzerland/France
- Inventor
- Marc Birkigt
- Manufacturer
- Hispano-Suiza
- Standard
- Military · Not SAAMI standardized · Not standardized
- SAAMI
- Not SAAMI standardized
- Obsolete
- Obsolete
- Status
- Obsolete
- Availability
- Not commercially available
- Case capacity
- 559.6 gr H₂O
- Twist (typical)
- 1:24
- Primer
- Electric/percussion (military)
- Case type
- Rimless
- Max pressure
- 18,000 psi, CIP transducer
- Eff. range
- 600 yd
- Max range
- 4500 yd
- Recoil
- 688.8–709.5 ft·lb
Ballistics
Velocity only, no drag model: no published ballistic coefficient is on file for 20mm Hispano, so this is the shape gravity alone gives the advertised velocity. Drag would steepen it. The tool below solves real loads through their published G1 or G7 model.
Open in Ballistic Compare- Parent case
- —
Representative trajectory — modeled from a single velocity input (no published BC for this cartridge yet).
Dimensionscase measurements · scale drawing · size vs familiar rounds
Case dimensions — the scale drawing at the top of the page is built from these.
Wikipedia · approximate| Measure | mm | in | ✓ |
|---|---|---|---|
| Bullet ⌀ | 20.00 | 0.787 | ~ |
| Neck ⌀ | 20.87 | 0.822 | |
| Shoulder ⌀ | 23.26 | 0.916 | |
| Shoulder angle | 23° | — | |
| Base ⌀ | 24.50 | 0.965 | ~ |
| Rim ⌀ | 24.50 | 0.965 | ~ |
| Belt ⌀ | n/a | ||
| Rim thickness | 2.71 | 0.107 | |
| Neck length | 20.65 | 0.813 | |
| Case length | 110.10 | 4.335 | · |
| Overall length | 184.00 | 7.244 | · |
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. 20mm Hispano is highlighted below.
Missing a dimension for 20mm Hispano? Some case measurements aren't in a published SAAMI/CIP drawing yet. Have a factory or reamer print? Send it → — verified hard-to-find data earns a free Lindcott sticker.
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
Designed by Marc Birkigt at Hispano-Suiza in the 1930s, the HS.404 and its 20×110mm round armed the Spitfire, Hurricane, Typhoon, and many U.S. aircraft. Its hitting power far exceeded rifle-caliber machine guns and drove the wartime shift to cannon armament in fighters.
FAQs
- What twist rate does 20mm Hispano use?
- 20mm Hispano typically uses a 1:24 twist rate.
- What bullet diameter is 20mm Hispano?
- 20mm Hispano uses a 0.7874″ (20 mm) diameter bullet.
- Is 20mm Hispano still in production?
- 20mm Hispano is obsolete; typical availability is not commercially available.
- What is 20mm Hispano used for?
- 20mm Hispano is primarily used for military.
Sources & provenance
Data & sources. Specs compiled from the Lindcott Armory reference; the trajectory is modeled (point-mass), not measured. See methodology. Spotted an error? Report it →
