Pistol · Not SAAMI standardized · Not standardizedObsolete
.31 Volcanic
.31 Volcanic is a caseless straight-walled pistol cartridge of United States origin.
- Caliber
- 0.3098″ · 7.87 mm
- Introduced
- 1854
- Case
- Caseless
- Primary use
- Self-Defense, Target
- Status
- Obsolete
- Obsolete
- Obsolete
- Introduced
- 1854
- Type
- Pistol
- Origin
- United States
- Inventor
- Walter Hunt (Rocket Ball); Smith & Wesson / Volcanic
- Manufacturer
- Volcanic Repeating Arms / Smith & Wesson
- Standard
- Not SAAMI standardized · Not standardized
- SAAMI
- Not SAAMI standardized
- Obsolete
- Obsolete
- Status
- Obsolete
- Availability
- Collector
- Twist (typical)
- 1:16
- Primer
- Small Pistol
- Case type
- Caseless
- Eff. range
- 50 yd
- Max range
- 250 yd
- Recoil
- 1.4–1.7 ft·lb
Ballistics
Velocity only, no drag model: no published ballistic coefficient is on file for .31 Volcanic, 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.
mixed/other · approximate| Measure | mm | in | ✓ |
|---|---|---|---|
| Bullet ⌀ | 7.87 | 0.310 | · |
| Neck ⌀ | — | — | |
| Shoulder ⌀ | n/a | ||
| Shoulder angle | n/a | ||
| Base ⌀ | 7.87 | 0.310 | ~ |
| Rim ⌀ | 7.87 | 0.310 | ~ |
| Belt ⌀ | n/a | ||
| Rim thickness | — | — | |
| Neck length | n/a | ||
| Case length | 29.25 | 1.152 | ~ |
| Overall length | 29.25 | 1.152 | |
Missing a dimension for .31 Volcanic? 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 .31 Volcanic
Connected reference
History
Introduced around 1854 by Walter Hunt (Rocket Ball); Smith & Wesson / Volcanic.
FAQs
- What twist rate does .31 Volcanic use?
- .31 Volcanic typically uses a 1:16 twist rate.
- What bullet diameter is .31 Volcanic?
- .31 Volcanic uses a 0.3098″ (7.87 mm) diameter bullet.
- Is .31 Volcanic still in production?
- .31 Volcanic is obsolete; typical availability is collector.
- What is .31 Volcanic used for?
- .31 Volcanic is primarily used for self-defense, target.
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 →
