The .425 Westley Richards (11×84mm) is one of the classic African big-game rounds. It is a cartridge invented by the Westley Richards gun making firm of Birmingham England in 1909 as a proprietary cartridge for their bolt action rifles.

This cartridge is often referred to as the "Poor Man's Magnum" because it was chambered in custom built, large ring, Mauser 98, bolt actions rifles. The round had an unusual rebated rim. This design was to take advantage of stripper clip ammunition that had the “standard” bolt face [.473 in (12 mm)] from the 8 x 57mm Mauser cartridge.

Another particularity to this cartridge is that despite its name “.425” it uses a .435 in (11.05 mm) diameter bullet.

Cartridge SpecificationsEdit

.425 Westley Richards
.425 Westley Richards

Production HistoryEdit

Type Commmercial Cartridge
Place of Origin United Kingdom
Designer Westley Richards Co.
Designed 1910
Manufacturer Westley Richards
Production 1910 to present with some interruptions
Parent Case None
Case Type Rebated Rim Bottleneck


Bullet Diameter .435 in (11.05 mm)
Cartridge Length 3.34 in (84.8 mm)
Case Length 2.64 in (67.1 mm)
Base to Neck 1.94 in (49.3 mm)
Base to Shoulder 1.72 in (43.7 mm)
Neck Diameter .456 in (11.6 mm)
Shoulder Diameter .530 in (13.5 mm)
Basic Diameter .543 in (13.8 mm) / Height .200 (5.08 mm)
Rim Diameter .467 in (11.9 mm)
Shoulder Angle 8 degrees 30 minuets
Case Capacity 112 gr (7.29 cc)


Bullet Type (1) .435 in (11.05mm) 410 gr (26.6 g) RNSP
Muzzle Velocity 2410 ft/s (735 m/s)
Muzzle Energy 5288 ft-lbf (7170 J)
Barrel Length 24 in (610 mm)
Source The Handloaders Manual of Cartridge Conversion


The .425 Westley Richards cartridge is believed to be responsible for the great dislike in rebated rim cases. It was wrongly believed that a rebated rim design was subject to frequent chambering and feeding failure.

The event was the bolt riding over the top of the rim and either jamming into the body of the round or misfeeding it completely.

It has been shown that it was the conversion of used military Mauser rifles with worn and weak magazine springs that were the cause of the suspected problem. These weak springs could not properly support and push up on the much heavier .425 Westley Richards cartridge. The military Mauser magazine spring was designed for the much lighter 7 x 57mm Mauser cartridge.

The Westley Richards Best Quality military mauser action was modified to reflect a single stacked magazine in concert with clip springs in the top of the receiver to allow the cartridge to ride higher in the receiver than usual so the bolt would positively engage the rebated rim. The only complaint with this rifle was with the standard 5 round capacity magazine wherein the follower spring would weaken over time and the first in, last out, cartridge might not ride high enough to allow the bolt face to contact the rebated rim, thus causing a misfeed. The White Hunter mauser rifle that Westley Richards produced for the colonial trade incorporated a non-modified military mauser action where the large diameter case and rebated rim of the 425 WR did not fit well with the staggered magazine box for the standard 8mm mauser cartridge. This White Hunter model is the rifle which gained the poor reputation for misfeeds with the cartridge and the ultimate dislike of rebated rim cartridges in general.

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