Pistol · Obsolete / Non-standard
.38 Rimfire
Smith & Wesson's .38-caliber rimfire revolver cartridge, used in the S&W No.
- Caliber
- 0.374″ · 9.5 mm
- Introduced
- 1861
- Case
- Rimfire
- Primary use
- Self-Defense, Military
- Status
- Obsolete
- Introduced
- 1861
- Type
- Pistol
- Origin
- United States
- Inventor
- Smith & Wesson
- Manufacturer
- Various (historical)
- Standard
- Obsolete / Non-standard
- Status
- Obsolete
- Availability
- Collector Only
- Case capacity
- 12 gr H₂O
- Twist (typical)
- 1:18.75
- Primer
- Rimfire
- Case type
- Rimfire
- Max pressure
- 12,000 psi
- Eff. range
- 25 yd
- Max range
- 75 yd
- Recoil
- 1.5–2.5 ft·lb
- Subsonic
- Capable
Ballistics
Published velocity/energy data isn't available for .38 Rimfire — 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.
Wikipedia · approximate| Measure | mm | in | ✓ |
|---|---|---|---|
| Bullet ⌀ | 9.50 | 0.374 | ~ |
| Neck ⌀ | 9.55 | 0.376 | · |
| Shoulder ⌀ | n/a | ||
| Shoulder angle | n/a | ||
| Base ⌀ | 9.60 | 0.378 | · |
| Rim ⌀ | 11.00 | 0.433 | · |
| Belt ⌀ | n/a | ||
| Rim thickness | 1.30 | 0.051 | ~ |
| Neck length | n/a | ||
| Case length | 18.54 | 0.730 | · |
| Overall length | 30.35 | 1.195 | · |
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. .38 Rimfire is highlighted below.
Factory loads
Being verified
Advertised FPS, energy, and BC are withheld until loads clear verification.
Connected reference
History
Smith & Wesson introduced the No. 2 Army revolver in 1861, chambered in .38 rimfire. Though the US government did not officially issue the revolver, demand from soldiers purchasing their own sidearms was enormous — S&W produced over 77,000 No. 2 revolvers during the Civil War. The cartridge gave a meaningful power advantage over the .32 rimfire used in the smaller S&W No. 1. As centerfire technology matured in the 1870s, rimfire pistol cartridges lost ground rapidly; the .38 S&W centerfire replaced the .38 rimfire in the marketplace. Original S&W No. 2 revolvers in shootable condition are prized Civil War collectibles. No current commercial production of .38 rimfire ammunition exists.
FAQs
- What twist rate does .38 Rimfire use?
- .38 Rimfire typically uses a 1:18.75 twist rate.
- What bullet diameter is .38 Rimfire?
- .38 Rimfire uses a 0.374″ (9.5 mm) diameter bullet.
- Is .38 Rimfire still in production?
- .38 Rimfire is obsolete; typical availability is collector only.
- What is .38 Rimfire used for?
- .38 Rimfire is primarily used for self-defense, military.
Sources & provenance
Data & sources. Specs compiled from the Lindcott Armory reference; availability counted from 20 live factory loads; the trajectory is modeled (point-mass), not measured. See methodology. Spotted an error? Report it →