Rifle · Not SAAMI standardized · Not standardizedObsolete
.375/303 Westley Richards Accelerated Express
.375/303 Westley Richards Accelerated Express is a rimmed bottlenecked rifle cartridge of United Kingdom origin.
- Caliber
- 0.311″ · 7.899 mm
- Introduced
- 1905
- Case
- Rimmed
- Parent
- .375 Flanged Nitro Express
- Primary use
- Hunting
- Status
- Obsolete
- Obsolete
- Obsolete
- Introduced
- 1905
- Type
- Rifle
- Origin
- United Kingdom
- Inventor
- Westley Richards
- Manufacturer
- Westley Richards
- Standard
- Not SAAMI standardized · Not standardized
- SAAMI
- Not SAAMI standardized
- Obsolete
- Obsolete
- Status
- Obsolete
- Availability
- Collector
- Case capacity
- 61.8 gr H₂O
- Twist (typical)
- 1:10
- Primer
- Large Rifle Magnum
- Case type
- Rimmed
- Max pressure
- 38,000 psi, CIP transducer
- Eff. range
- 300 yd
- Max range
- 1500 yd
- Recoil
- 19.4–22.3 ft·lb
Introduced by Westley Richards
Ballistics
Velocity only, no drag model: no published ballistic coefficient is on file for .375/303 Westley Richards Accelerated Express, 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
- .375 Flanged Nitro Express
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.
Wikipedia · approximate| Measure | mm | in | ✓ |
|---|---|---|---|
| Bullet ⌀ | 7.90 | 0.311 | · |
| Neck ⌀ | 8.71 | 0.343 | · |
| Shoulder ⌀ | 9.91 | 0.390 | · |
| Shoulder angle | 6.4° | — | |
| Base ⌀ | 11.61 | 0.457 | · |
| Rim ⌀ | 12.83 | 0.505 | · |
| Belt ⌀ | n/a | ||
| Rim thickness | 1.48 | 0.058 | |
| Neck length | 8.16 | 0.321 | |
| Case length | 63.50 | 2.500 | · |
| Overall length | 85.34 | 3.360 | · |
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. .375/303 Westley Richards Accelerated Express is highlighted below.
Missing a dimension for .375/303 Westley Richards Accelerated Express? 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.
Connected reference
History
Introduced around 1905 by Westley Richards, derived from the .375 Flanged Nitro Express.
FAQs
- What twist rate does .375/303 Westley Richards Accelerated Express use?
- .375/303 Westley Richards Accelerated Express typically uses a 1:10 twist rate.
- What bullet diameter is .375/303 Westley Richards Accelerated Express?
- .375/303 Westley Richards Accelerated Express uses a 0.311″ (7.899 mm) diameter bullet.
- Is .375/303 Westley Richards Accelerated Express still in production?
- .375/303 Westley Richards Accelerated Express is obsolete; typical availability is collector.
- What is .375/303 Westley Richards Accelerated Express used for?
- .375/303 Westley Richards Accelerated Express is primarily used for hunting.
- What is .375/303 Westley Richards Accelerated Express based on?
- .375/303 Westley Richards Accelerated Express is derived from the .375 Flanged Nitro Express case.
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 →
