Lindcott Armory Rimfire · Proprietary
.56-46 Spencer
Necked-down Spencer family rimfire cartridge developed for improved velocity in post-Civil War Spencer sporting and military conversion rifles..
- Caliber
- 0.465″ · 11.81 mm
- Introduced
- 1866
- Case
- Rimmed
- Status
- Discontinued
- Introduced
- 1866
- Type
- Rimfire
- Origin
- United States
- Inventor
- Christopher Spencer
- Standard
- Proprietary
- Status
- Discontinued
- Availability
- Rare
- Primer
- Rimfire
- Case type
- Rimmed
- Eff. range
- 200 yd
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 ⌀ | 11.81 | 0.465 | ~ |
| Neck ⌀ | 12.32 | 0.485 | ~ |
| Shoulder ⌀ | — | — | |
| Shoulder angle | — | — | |
| Base ⌀ | 14.22 | 0.560 | ~ |
| Rim ⌀ | 16.38 | 0.645 | ~ |
| Belt ⌀ | n/a | ||
| Rim thickness | — | — | |
| Neck length | — | — | |
| Case length | 26.42 | 1.040 | ~ |
| Overall length | — | — | |
Missing a dimension for .56-46 Spencer? 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.
Connected reference
History
The .56-46 Spencer was developed after the Civil War as an improved loading for the Spencer repeating rifle, using a necked case to achieve higher velocity than the straight-walled .56-56 Spencer. It was used in later Spencer production and conversion rifles through the late 1860s before lever-action centerfire arms supplanted rimfire Spencers.
FAQs
- What bullet diameter is .56-46 Spencer?
- .56-46 Spencer uses a 0.465″ (11.81 mm) diameter bullet.
- Is .56-46 Spencer still in production?
- .56-46 Spencer is discontinued; typical availability is rare.
Sources & provenance
- ReferenceGun Digest Books — Cartridges of the World (Frank C. Barnes) — obsolete rimfire section, .56-46 Spencer entry · year, velocity, grain weights, bullet ⌀
- SecondaryWikipedia — .56-56 Spencer (covers the .56-46 necked variant) · bullet ⌀, grain weightsarchived
Data & sources. Specs compiled from the Lindcott Armory reference; the trajectory is modeled (point-mass), not measured. See methodology. Spotted an error? Report it →