Rahul Sharma (Editor)

.333 Jeffery

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In service

World War I

Place of origin
Used by
W.J. Jeffery & Co

The .333 Jeffery and .333 Jeffery Flanged are medium bore centrefire rifle cartridges developed by W.J. Jeffery & Co and introduced in 1908.


.333 Jeffery

The .333 Jeffery also known as the .333 Jeffery Rimless Nitro Express or as the .333 Rimless Nitro Express is a rimless bottlenecked cartridge intended for use in magazine rifles, derived from the .404 Jeffery, it could be used in both standard and magnum length Mauser 98 actions.

.333 Jeffery Flanged

The .333 Jeffery Flanged or .333 Flanged Nitro Express is the rimmed version of the . 333 Jeffery, intended for use in single shot and double rifles. It is loaded to slightly lower velocities than the rimless .333 Jeffery.


The .333 Jeffery was originally released with two factory loads, a 250 gr (16 g) bullet fired at 2,500 ft/s (760 m/s) and a 300 gr (19 g) bullet fired at 2,200 ft/s (670 m/s). The 300 gr round has a very high sectional density and exceptional penetration. Unfortunately the original 250 gr bullet was a copper-capped hollowpoint that was too fragile to be fired at 2,500 fps, making it unpopular and marring the .333 Jeffery's reputation for some time.

As with many British proprietary cartridges, the .333 Jeffery was forced into obsolescence when Kynoch suspended ammunition manufacturing in the 1960s. Kynamco resumed manufacture of the Kynoch range of cartridges in the 1990s meaning the ammunition is again commercially available, although no firearms manufacturers make factory rifles in .333 Jeffery today.


While the cartridge is not intended for dangerous game, due to its excellent penetration the 300 gr round has been successfully used on all African game species up to elephant.

In his African Rifles and Cartridges, John "Pondoro" Taylor wrote of the .333 Jeffery "Time and again have I driven it the length of an animal’s body, and cut the perfectly mushroomed bullet out of his hindquarters. I have never had one break up."

The cartridge was very similar in performance to the .318 Westley Richards, it was somewhat overshadowed by the arrival of the .375 Holland & Holland.

The .280 Jeffery was created by Jeffery by necking down their successful .333 Jeffery to .288 inches.

WWI service

In 1914 and early 1915, German snipers were engaging British Army positions with impunity from behind steel plates that were impervious to .303 British ball ammunition. In an attempt to counter this threat, the British War Office purchased a number of larger calibre sporting rifles from British rifle makers, including .333 Jeffery rifles.

In his Sniping in France 1914-18, MAJ H. Hesketh-Prichard, DSO, MC, stated "I proceeded to try on these plates all kinds of rifles, from Jeffery’s high velocity .333 to heavy elephant guns of various bores, and was delighted to find the bullets from the .333, as well as the elephant guns, pierced them like butter."


.333 Jeffery Wikipedia