Lindcott Armory Rifle · NATO
20mm Vulcan
The standard cannon cartridge of American fighter aircraft for 70 years.
- Caliber
- 0.7874″ · 20 mm
- Introduced
- 1956
- Case
- Rimless
- Primary use
- Military, Anti-Aircraft, Air-to-Air
- Status
- Active
- Introduced
- 1956
- Type
- Rifle
- Origin
- United States
- Inventor
- General Electric / U.S. Ordnance
- Manufacturer
- General Dynamics Ordnance and Tactical Systems
- Standard
- NATO
- Status
- Active
- Availability
- Restricted
- Case capacity
- 400 gr H₂O
- Twist (typical)
- 1:24
- Primer
- Electric Primer
- Case type
- Rimless
- Max pressure
- 65,000 psi
- Eff. range
- 2000 yd
- Max range
- 6000 yd
- Recoil
- 150–200 ft·lb
Ballistics
- 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.
SAAMI · approximate| Measure | mm | in | ✓ |
|---|---|---|---|
| Bullet ⌀ | 20.00 | 0.787 | · |
| Neck ⌀ | 21.08 | 0.830 | ~ |
| Shoulder ⌀ | 26.67 | 1.050 | ~ |
| Shoulder angle | — | — | |
| Base ⌀ | 29.21 | 1.150 | ~ |
| Rim ⌀ | 29.50 | 1.161 | · |
| Belt ⌀ | n/a | ||
| Rim thickness | — | — | |
| Neck length | — | — | |
| Case length | 102.00 | 4.016 | · |
| Overall length | 168.00 | 6.614 | ~ |
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 Vulcan is highlighted below.
Missing a dimension for 20mm Vulcan? 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.
Firearms chambered in 20mm Vulcan
2 models in the database chamber 20mm Vulcan. Browse all →
Connected reference
History
Developed as the primary armament for post-WWII jet fighters, replacing .50 BMG as aircraft speeds made rifle-caliber guns insufficiently destructive. The M61 Vulcan cannon fires this cartridge at 6,000 rounds per minute from a six-barrel rotating mechanism — meaning a one-second burst delivers 100 rounds of 20mm projectiles. Armed virtually every American combat aircraft from the F-104 Starfighter through the F-22 Raptor and F-35. Ground variants arm the M163 VADS air defense system and the Phalanx CIWS naval close-in weapon system. The cartridge is technically a sporting cartridge under ATF rules if the projectile is not classified as explosive or incendiary — civilians can legally own 20mm Vulcan cases and inert projectiles, and a handful of civilians have built single-shot 20mm rifles. In practice, obtaining live military ammunition is essentially impossible without government contracts.
FAQs
- What twist rate does 20mm Vulcan use?
- 20mm Vulcan typically uses a 1:24 twist rate.
- What bullet diameter is 20mm Vulcan?
- 20mm Vulcan uses a 0.7874″ (20 mm) diameter bullet.
- Is 20mm Vulcan still in production?
- 20mm Vulcan is active; typical availability is restricted.
- What is 20mm Vulcan used for?
- 20mm Vulcan is primarily used for military, anti-aircraft, air-to-air.
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 →