Rifle · Not SAAMI standardized · Not standardizedObsolete
.577 Express 2 1/2"
Black powder express cartridge in .577 caliber with 2.5 inch case.
- Caliber
- 0.584″ · 14.834 mm
- Introduced
- 1875
- Case
- Rimmed
- Parent
- .577 Black Powder Express
- Primary use
- hunting
- Status
- Obsolete
- Obsolete
- Obsolete
- Introduced
- 1875
- Type
- Rifle
- Origin
- United Kingdom
- Inventor
- Various British
- Manufacturer
- British gunsmiths / Kynoch
- Standard
- Not SAAMI standardized · Not standardized
- SAAMI
- Not SAAMI standardized
- Obsolete
- Obsolete
- Status
- Obsolete
- Availability
- Antique
- Case capacity
- 150 gr H₂O
- Twist (typical)
- 1:20
- Primer
- Large Rifle
- Case type
- Rimmed
- Max pressure
- 18,000 psi, CIP transducer
- Eff. range
- 150 yd
- Max range
- 3700 yd
- Recoil
- 106.9–112.2 ft·lb
Ballistics
Published velocity/energy data isn't available for .577 Express 2 1/2" — an obsolete/collector cartridge. Parent case: .577 Black Powder Express.
Performance
Dimensionscase measurements · scale drawing · size vs familiar rounds
Case dimensions — the scale drawing at the top of the page is built from these.
Dimensions · secondary source| Measure | mm | in | ✓ |
|---|---|---|---|
| Bullet ⌀ | 14.83 | 0.584 | · |
| Neck ⌀ | 15.44 | 0.608 | · |
| Shoulder ⌀ | n/a | ||
| Shoulder angle | n/a | ||
| Base ⌀ | 16.76 | 0.660 | · |
| Rim ⌀ | 18.49 | 0.728 | · |
| Belt ⌀ | n/a | ||
| Rim thickness | 1.32 | 0.052 | · |
| Neck length | n/a | ||
| Case length | 63.50 | 2.500 | · |
| Overall length | 80.21 | 3.158 | |
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. .577 Express 2 1/2" 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
History
A British Express cartridge for large-bore double rifles, designed for medium dangerous game at close range. The 2.5-inch case held sufficient black powder for modest velocity; an early attempt to standardize British dangerous game ammunition before nitro express replaced all black powder designs.
FAQs
- What twist rate does .577 Express 2 1/2" use?
- .577 Express 2 1/2" typically uses a 1:20 twist rate.
- What bullet diameter is .577 Express 2 1/2"?
- .577 Express 2 1/2" uses a 0.584″ (14.834 mm) diameter bullet.
- Is .577 Express 2 1/2" still in production?
- .577 Express 2 1/2" is obsolete; typical availability is antique.
- What is .577 Express 2 1/2" used for?
- .577 Express 2 1/2" is primarily used for hunting.
- What is .577 Express 2 1/2" based on?
- .577 Express 2 1/2" is derived from the .577 Black Powder Express case.
Sources & provenance
Data & sources. Specs compiled from the Lindcott Armory reference; availability counted from 3 live factory loads; the trajectory is modeled (point-mass), not measured. See methodology. Spotted an error? Report it →
