What twist rate does .333 Jeffery use?

.333 Jeffery typically uses a 1:10 twist rate.

What bullet diameter is .333 Jeffery?

.333 Jeffery uses a 0.333″ (8.458 mm) diameter bullet.

Is .333 Jeffery still in production?

.333 Jeffery is obsolete; typical availability is antique.

What is .333 Jeffery used for?

.333 Jeffery is primarily used for hunting.

What is .333 Jeffery based on?

.333 Jeffery is derived from the .404 Jeffery case.

Lindcott Armory

Rifle · Obsolete

.333 Jeffery

Jeffrey's powerful British rifle cartridge for dangerous game.

Caliber: 0.333″ · 8.458 mm
Introduced: 1908
Case: Rimless
Parent: .404 Jeffery
Primary use: Hunting
Status: Obsolete

Buy this cartridge

Buy at Rivertown

Buying from Rivertown

Partner link

VelocityBeing verified

EnergyBeing verified

Typical grains250 gr

Identity

Introduced: 1908
Type: Rifle
Origin: United Kingdom
Inventor: W.J. Jeffery & Co.
Manufacturer: W.J. Jeffery & Co.
Standard: Obsolete
Status: Obsolete
Availability: Antique

Build

Case capacity: 78 gr H₂O
Twist (typical): 1:10
Primer: Boxer Large Rifle
Case type: Rimless

Pressure & range

Max pressure: 47,000 psi
Eff. range: 250 yd
Recoil: 12–18 ft·lb

Ballistics

Published velocity/energy data isn't available for .333 Jeffery — an obsolete/collector cartridge. Parent case: .404 Jeffery.

Performance

Best for Withheld until verified

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 ⌀	8.46	0.333	·
Neck ⌀	9.12	0.359	·
Shoulder ⌀	12.60	0.496	·
Shoulder angle	—	—
Base ⌀	13.72	0.540	·
Rim ⌀	13.66	0.538	·
Belt ⌀	n/a
Rim thickness	1.27	0.050	·
Neck length	—	—
Case length	62.99	2.480	~
Overall length	88.39	3.480	~

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. .333 Jeffery is highlighted below.

Missing a dimension for .333 Jeffery? 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.

Factory loads

Verification

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.

Powder $/lb Charge (gr) Bullet $/ea Primer $/ea Brass reuses Brass $/ea

Cost estimate only — not load data. Charge weight is your input; follow published manuals for safe charges.

Lineage

Family TreeOpen .333 Jeffery in the interactive cartridge family tree

Connected reference

FirearmsFirearms in .333 Jeffery

History

Developed by W.J. Jeffery & Co. of London around 1908. Designed for African dangerous game, the .333 Jeffery launched 300-grain bullets at modest velocity with excellent sectional density for deep penetration. Influenced later .338 caliber cartridges; especially .338 Winchester Magnum which is its spiritual successor.

FAQs

What twist rate does .333 Jeffery use?: .333 Jeffery typically uses a 1:10 twist rate.
What bullet diameter is .333 Jeffery?: .333 Jeffery uses a 0.333″ (8.458 mm) diameter bullet.
Is .333 Jeffery still in production?: .333 Jeffery is obsolete; typical availability is antique.
What is .333 Jeffery used for?: .333 Jeffery is primarily used for hunting.
What is .333 Jeffery based on?: .333 Jeffery is derived from the .404 Jeffery case.

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 →