Revolver · SAAMI
.256 Winchester Magnum
Bottlenecked revolver/carbine cartridge sharing the same concept as the .22 Remington Jet — rifle velocity from a handgun.
- Caliber
- 0.2571″ · 6.53 mm
- Introduced
- 1961
- Case
- Rimmed
- Parent
- .357 Magnum
- Primary use
- Varmint, Hunting
- Status
- Discontinued
- Introduced
- 1961
- Type
- Revolver
- Origin
- United States
- Inventor
- Winchester
- Manufacturer
- Winchester Ammunition
- Standard
- SAAMI
- Status
- Discontinued
- Availability
- Collector
- Case capacity
- 15.1 gr H₂O
- Twist (typical)
- 1:14
- Primer
- Small Pistol
- Case type
- Rimmed
- Max pressure
- 42,000 psi
- Eff. range
- 150 yd
- Max range
- 300 yd
- Recoil
- 8–12 ft·lb
Introduced by Winchester Ammunition
Ballistics
Published velocity/energy data isn't available for .256 Winchester Magnum — an obsolete/collector cartridge. Parent case: .357 Magnum (necked down).
Performance
Dimensionscase measurements · scale drawing · size vs familiar rounds
Case dimensions — the scale drawing at the top of the page is built from these.
CIP TDCC · verified| Measure | mm | in | ✓ |
|---|---|---|---|
| Bullet ⌀ | 6.53 | 0.257 | ✓ |
| Neck ⌀ | 7.24 | 0.285 | ✓ |
| Shoulder ⌀ | 9.35 | 0.368 | ✓ |
| Shoulder angle | 25° | — | ✓ |
| Base ⌀ | 9.68 | 0.381 | ✓ |
| Rim ⌀ | 11.18 | 0.440 | ✓ |
| Belt ⌀ | n/a | ||
| Rim thickness | 1.52 | 0.060 | ✓ |
| Neck length | 5.29 | 0.208 | ≈ |
| Case length | 32.54 | 1.281 | ✓ |
| Overall length | 40.39 | 1.590 | ✓ |
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. .256 Winchester Magnum is highlighted below.
Factory loads
Being verified
Advertised FPS, energy, and BC are withheld until loads clear verification.
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.
Lineage
Connected reference
History
Introduced alongside the .22 Remington Jet in 1961 as competing entries in the high-velocity revolver concept. Winchester's version chambered in the Ruger Hawkeye single-shot pistol and the Marlin 62 carbine. Like the Jet, it suffered from the revolver case-setback problem and never achieved commercial success. Factory ammunition was discontinued in the 1970s. The Marlin 62 carbine is now a collector item.
FAQs
- What twist rate does .256 Winchester Magnum use?
- .256 Winchester Magnum typically uses a 1:14 twist rate.
- What bullet diameter is .256 Winchester Magnum?
- .256 Winchester Magnum uses a 0.2571″ (6.53 mm) diameter bullet.
- Is .256 Winchester Magnum still in production?
- .256 Winchester Magnum is discontinued; typical availability is collector.
- What is .256 Winchester Magnum used for?
- .256 Winchester Magnum is primarily used for varmint, hunting.
- What is .256 Winchester Magnum based on?
- .256 Winchester Magnum is derived from the .357 Magnum (necked down) case.
Sources & provenance
- Standard SAAMI — ANSI/SAAMI Z299 — Cartridge & Chamber Drawings archived
- Standard C.I.P. — C.I.P. TDCC — Tables of Dimensions of Cartridges and Chambers
- Standard SAAMI — ANSI/SAAMI Z299.3-1993, Velocity and Pressure Data — Centerfire Pistol and Revolver Cartridges (archived saami.org PDF, Wayback snapshot 2010-11-29) · grain_ballistics, representative_gun
- Manufacturer Ventura Munitions (Ventura Heritage house line) — Ventura Heritage 256 Winchester Magnum 86gr SP New Ammo — 20 Rounds (product spec sheet) · grain_ballistics, representative_gun archived
Data & sources. Specs compiled from the Lindcott Armory reference; availability counted from 17 live factory loads; the trajectory is modeled (point-mass), not measured. See methodology. Spotted an error? Report it →