.303 British (designated as the 303 British by the C.I.P. and
SAAMI) or 7.7×56mmR, is a .303-inch (7.7 mm) calibre (with
the bore diameter measured between the lands as is common practice in
Europe) rimmed rifle cartridge first developed in Britain as a
black-powder round put into service in December 1888 for the
Lee–Metford rifle. In 1891 the cartridge was adapted to use
smokeless powder. It was the standard British and Commonwealth
military cartridge from 1889 until the 1950s when it was replaced by
the 7.62×51mm NATO.
1 Cartridge dimensions
2 Military use
2.1 History and development
2.4 Mark II – Mark VI
2.5 Mark VII
2.5.1 .276 Enfield
2.6 Mark VIII
2.7 Tracer, armour-piercing and incendiary
3 Military surplus ammunition
4 Headstamps and colour-coding
5 Japanese 7.7 mm ammunition
6 Civil use
6.1 .303 Epps
6.2 Commercial ammunition and reloading
6.3 Hunting use
7 Firearms chambered for .303 British
8 See also
10 External links
.303 British has 3.64 ml (56 grains H2O) cartridge case capacity.
The pronounced tapering exterior shape of the case was designed to
promote reliable case feeding and extraction in bolt action rifles and
machine guns alike, under challenging conditions.
.303 British maximum
C.I.P. cartridge dimensions. All sizes in
Americans would define the shoulder angle at alpha/2 ≈ 17 degrees.
The common rifling twist rate for this cartridge is 254 mm
(10.0 in) 10 in), 5 grooves, Ø lands = 7.70 millimetres
(0.303 in), Ø grooves = 7.92 millimetres (0.312 in), land
width = 2.12 millimetres (0.083 in) and the primer type is Berdan
or Boxer (in large rifle size).
According to the official
C.I.P. (Commission Internationale Permanente
pour l'Epreuve des Armes à Feu Portatives) rulings the .303 British
can handle up to 365.00 MPa (52,939 psi) Pmax piezo
C.I.P. regulated countries every rifle cartridge combo
has to be proofed at 125% of this maximum
C.I.P. pressure to certify
for sale to consumers. This means that
.303 British chambered arms
C.I.P. regulated countries are currently (2014) proof tested at
456.00 MPa (66,137 psi) PE piezo pressure.
SAAMI (Sporting Arms and Ammunition Manufacturers' Institute)
Maximum Average Pressure (MAP) for this cartridge is 49,000 psi
(337.84 MPa) piezo pressure (45,000 CUP).
The measurement .303-inch (7.70 mm) is the nominal size of the
bore measured between the lands which follows the older black powder
nomenclature. Measured between the grooves, the nominal size of the
bore is .311-inch (7.90 mm). Bores for many .303 military surplus
rifles are often found ranging from around .309-inch (7.85 mm) up
to .318-inch (8.08 mm). Recommended bullet diameter for standard
.303 British cartridges is .312-inch (7.92 mm).
History and development
During a service life of over 70 years with the British Commonwealth
armed forces the .303-inch cartridge in its ball pattern progressed
through ten marks which eventually extended to a total of about 26
variations. The bolt thrust of the
.303 British is relatively low
compared to many other service rounds used in the early 20th century.
.303 British service cartridge employed black powder as a
propellant, and was adopted for the
Lee–Metford rifle, which had
rifling designed to lessen fouling from this propellant. The
Lee–Metford was used as a trial platform by the British Committee on
Explosives to experiment with many different smokeless powders then
coming to market, including Ballistite, Cordite, and
Ballistite was a stick-type smokeless powder
composed of soluble nitrocellulose and nitroglycerine.
a stick-type or 'chopped' smokeless gunpowder composed of
nitroglycerine, gun-cotton, and mineral jelly, while Rifleite was a
true nitrocellulose powder, composed of soluble and insoluble
nitrocellulose, phenyl amidazobense, and volatiles similar to French
smokeless powders. Unlike Cordite, Riflelite was a flake
powder, and contained no nitroglycerine. Excessive wear of the
Lee–Metford rifling with all smokeless powders then
available caused ordnance authorities to institute a new type of
barrel rifling designed by the RSAF, Enfield, to increase barrel life;
the rifle was referred to thereafter as the Lee–Enfield. After
extensive testing, the Committee on Explosives selected
use in the Mark II
.303 British service cartridge.
The initial .303 Mark I and Mk II service cartridges employed a
215-grain, round-nosed, copper-nickel full-metal-jacketed bullet with
a lead core. After tests determined that the service bullet had too
thin a jacket when used with cordite, the Mk II bullet was introduced,
with a flat base and thicker copper-nickel jacket.
Mark II – Mark VI
Longitudinal section of Mk VI ammunition 1904, showing the round nose
The Mk II round-nosed bullet was found to be unsatisfactory when used
in combat, particularly when compared to the dum-dum rounds issued in
limited numbers in 1897 during the Chitral and Tirah expeditions of
1897/98 on the North West Frontier of India. This led to the
introduction of the Cartridge S.A. Ball .303 inch
III, basically the original 215-grain (13.9 g) bullet with the
jacketing cut back to expose the lead in the nose. Similar
hollow-point bullets were used in the Mk IV and Mk V loadings, which
were put into mass production. The design of the Mk IV hollow-point
bullet shifted bullet weight rearwards, improving stability and
accuracy over the regular round-nose bullet. These soft-nosed and
hollow-point bullets, while effective against human targets, had a
tendency to shed the outer metal jacket upon firing; the latter
occasionally stuck in the bore, causing a dangerous obstruction.
The Hague Convention of 1899 later declared that use of expanding
bullets against signatories of the convention was inhumane, and as a
result the Mk III, Mk IV, and Mk V were withdrawn from active service.
The remaining stocks (over 45 million rounds) were used for target
The concern about expanding bullets was brought up at the 1899 Hague
Convention by Swiss and Dutch representatives. The Swiss were
concerned about small arms ammunition that "increased suffering", and
the Dutch focused on the British Mark III .303 loading in response to
their treatment of
Boer settlers in South Africa. The British and
American defense was that they should not focus on specific bullet
designs, like hollow-points, but instead on rounds that caused
"superfluous injury". The parties in the end agreed to abstain from
using expanding bullets. As a result, the Mark III and other expanding
versions of the .303 were not issued during the Second
Boer guerrillas allegedly used expanding hunting
ammunition against the British during the war, and New Zealand
Commonwealth troops may have brought Mark III rounds with them
privately after the Hague Convention without authorization.
To replace the Mk III, IV, and V, the Mark VI round was introduced in
1904, using a round nose bullet similar to the Mk II, but with a
thinner jacket designed to produce some expansion, though this proved
not to be the case.
Longitudinal section of Mk VII ammunition circa 1915, showing the
"tail heavy" design
In 1898, APX (Atelier de Puteaux), with their "Balle D" design for the
8mm Lebel cartridge, revolutionised bullet design with the
introduction of pointed "spitzer" rounds. In addition to being
pointed, the round was also much lighter in order to deliver a higher
muzzle velocity. It was found that as velocity increased the bullets
suddenly became much more deadly.
In 1910, the British took the opportunity to replace their Mk VI
cartridge with a more modern design. The Mark VII loading used a 174
grains (11.3 g) pointed bullet with a flat-base. The .303 British
Mark VII cartridge had a muzzle velocity of 2,440 ft/s
(744 m/s) and a maximum range of approximately 3,000 yd
(2,700 m).  The Mk VII was different from earlier .303
bullet designs or spitzer projectiles in general. Although it appears
to be a conventional spitzer-shape full metal jacket bullet, this
appearance is deceptive: its designers made the front third of the
interior of the Mk 7 bullets out of aluminium (from Canada) or tenite
(cellulosic plastic), wood pulp or compressed paper, instead of lead
and they were autoclaved to prevent wound infection. This lighter nose
shifted the centre of gravity of the bullet towards the rear, making
it tail heavy. Although the bullet was stable in flight due to the
gyroscopic forces imposed on it by the rifling of the barrel, it
behaved very differently upon hitting the target. As soon as the
bullet hit the target and decelerated, its heavier lead base caused it
to pitch violently and deform, thereby inflicting more severe gunshot
wounds than a standard single-core spitzer design. In spite of
this, the Mk VII bullet was legal due to the full metal jacket used
according to the terms of the Hague Convention.
The Mk VII (and later Mk VIII) rounds have versions utilizing
nitrocellulose flake powder smokeless propellants. The nitrocellulose
versions—first introduced in World War I—were designated with a
"Z" postfix indicated after the type (e.g. Mark VIIZ, with a weight of
175 grains) and in headstamps.
.303 British cartridges, along with the
Lee–Enfield rifle, were
heavily criticized after the Second
Boer War. Their heavy round-nosed
bullets had low muzzle velocities and suffered compared to the 7×57mm
rounds fired from the Mauser Model 1895. The high-velocity
a flatter trajectory and longer range that excelled on the open
country of the South African plains. In 1910, work began on a
long-range replacement cartridge, which emerged in 1912 as the .276
Enfield. The British also sought to replace the
Pattern 1913 Enfield
Pattern 1913 Enfield rifle, based on the Mauser M98 bolt
action design. Although the round had better ballistics, troop trials
in 1913 revealed problems including excessive recoil, muzzle flash,
barrel wear and overheating. Attempts were made to find a
cooler-burning propellant, but further trials were halted in 1914 by
the onset of World War I. As a result, the
Lee–Enfield rifle was
retained, and the
.303 British cartridge (with the improved Mark VII
loading) was kept in service.
In 1938 the Mark VIII (Mark VIII and Mark VIIIz) round was approved to
obtain greater range from the Vickers machine gun. Slightly
heavier than Mk VII bullet at 175 grains (11.3 g), the primary
difference was the addition of a boat-tail and more propellant (41
grains of nitrocelluose powder in the case of the Mk VIIIz), giving a
muzzle velocity of 2,525–2,900 ft/s (770–884 m/s). As a
result, the chamber pressure was significantly higher, at
42,000–60,000 lbf/sq in (approximately 280–414 MPa), depending
upon loading, compared to the 39,000 lbf/sq in of the Mark VII
round. The Mark VIII cartridge had a maximum range of
approximately 4,500 yd (4,115 m). Mk VIII ammunition was
described as being for "All suitably-sighted .303-inch small arms and
machine guns" but caused significant bore erosion in weapons formerly
using Mk VII cordite, ascribed to the channelling effect of the
boat-tail projectile. As a result, it was prohibited from general use
with rifles and light machine guns except in emergency. As a
consequence of the official prohibition, ordnance personnel reported
that every man that could get his hands on Mk VIII ammunition promptly
used it in his own rifle.
Tracer, armour-piercing and incendiary
Tracer and armour-piercing cartridges were introduced during 1915,
with explosive bullets derived from John Pomeroy's work introduced as
the Mark VII.Y in 1916.
Several incendiaries were privately developed from 1914 to counter the
Zeppelin threat but none were approved until the Brock design late in
1916 as BIK Mark VII.K Wing Cmdr. Frank Brock RNVR, its inventor,
was a member of the Brock fireworks-making family. A later incendiary
was known as the de Wilde, which had the advantage of leaving no
visible trail when fired. The de Wilde was later used in some numbers
in fighter guns during the 1940 Battle of Britain.
These rounds were extensively developed over the years and saw several
Mark numbers. The last tracer round introduced into British service
was the G Mark 8 in 1945, the last armour-piercing round was the W
Mark 1Z in 1945 and the last incendiary round was the B Mark 7 in
1942. Explosive bullets were not produced in the UK after 1933 due to
the relatively small amount of explosive that could be contained in
the bullet, limiting their effectiveness, their role being taken by
the use of Mark 6 and 7 incendiary bullets.
In 1935 the .303 O Mark 1 Observing round was introduced for use in
machine guns. The bullet to this round was designed to break up with a
puff of smoke on impact. The later Mark 6 and 7 incendiary rounds
could also be used in this role.
World War I
World War I British factories alone produced 7,000,000,000
rounds of .303 ammunition. Factories in other countries added greatly
to this total.
Military surplus ammunition
.303 British ammunition is often
available[clarification needed], notably at gun shows and from online
dealers[who?]. It may or may not have corrosive primers. There is no
problem with using ammunition loaded with corrosive primers, providing
that the gun is thoroughly cleaned after use to remove the corrosive
salts.[according to whom?]
Care must be taken to identify the round properly before purchase or
loading into weapons.[according to whom?] Cartridges with the Roman
numeral VIII on the headstamp are the Mark 8 round, specifically
designed for use in Vickers machine guns. Although Mark 8 ammunition
works well in a Vickers gun, it should not be used in rifles because
the cordite powder causes increased barrel wear. The boat-tailed
bullet design of Mk 8 ammunition is not in itself a problem. However,
when combined with the cordite propellant used in Mk 8 cartridges,
which burns at a much higher temperature than nitrocellulose, there is
increased barrel erosion. The cumulative effects of firing Mk 8
ammunition through rifles were known during the Second World War, and
British riflemen were ordered to avoid using it, except in
emergencies. The best general-purpose ammunition for any .303 military
rifle is the Mark 7 design because it provides the best combination of
accuracy and stopping power.
Headstamps and colour-coding
.303 British Cartridge (Mk VII), manufactured by CAC in 1945
Primer Annulus Color
Bullet Tip Color
VII or VIIZ
G1, G2, G3, G7 or G8
G4, G4Z, G6 or G6Z
G5 or G5Z
W1 or W1Z
VIIF or VIIFZ
Semi-Armor Piercing (1916-1918)
Semi-Armor Piercing (1941)
B4 or B4Z
Step in bullet jacket
B6 or B6Z
B7 or B7Z
PG1 or PG1Z
Blue band on case base
Front half of case blackened
Entire case blackened
Case blackened 3/4" inch from each end
Rear Half of case blackened
Grenade Discharger (v.powerful load)
Japanese 7.7 mm ammunition
Cutaways of the five types of ammunition produced in Japan.
Japan produced a number of machine guns that were direct copies of the
British Lewis (Japanese Type 92 machine gun) and Vickers machine guns
including the ammunition. These were primarily used in Navy aircraft.
The 7.7mm cartridge used by the Japanese versions of the British guns
is a direct copy of the
.303 British (7.7×56mmR) rimmed cartridge and
is distinctly different from the
7.7×58mm Arisaka rimless and
7.7×58mm Type 92 semi-rimmed cartridges used in other Japanese
machine guns and rifles.
Ball: 174 grains (11.3 g). Cupro-Nickel jacket with a composite
aluminium/lead core. Black primer.
Armor-Piercing.: Brass jacket with a steel core. White primer.
Tracer: 130 grains (8.4 g). Cupro-Nickel jacket with a lead core.
Incendiary: 133 grains (8.6 g). Brass jacket with white
phosphorus and lead core. Green primer.
H.E.: Copper jacket with a
PETN and lead core. Purple primer.
Note: standard Japanese ball ammunition was very similar to the
British Mk 7 cartridge. The two had identical bullet weights and a
"tail-heavy" design, as can be seen in the cut-away diagram.
The .303 cartridge has seen much sporting use with surplus military
rifles, especially in Australia, Canada, New Zealand and to a lesser
extent, in the United States and South Africa. In Canada, it was found
to be adequate for any game except the great bears. In Australia, it
was common for military rifles to be re-barreled in
.303/22. However the .303 round still retains a considerable following
as a game cartridge for all game species, especially Sambar deer in
wooded country. A recent change.org petition seeking Lithgow Arms to
chamber the LA102 centerfires rifle in .303 as a special edition
release has attracted considerable attention both in
worldwide. In South Africa
Lee–Enfield rifles captured
by the Boers during the
Boer War were adapted for sporting purposes
and became popular with many hunters of non-dangerous game, being
regarded as adequate for anything from the relatively small impala, to
the massive eland and kudu.
A Canadian outdoors store, Ellwood Epps created an improved version of
the .303 British, using a slightly expanded case. While it has better
ballistic performance than standard .303 British, it suffers from
'case drooping', a condition which, over time, makes the cases slowly
unsafe to reload.
Commercial ammunition and reloading
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Commercial soft point
.303 British loaded in a Lee–Enfield
Civilian soft point .303 ammunition, suitable for hunting purposes.
.303 British is one of the few (along with the .22 Hornet, .30-30
Winchester, and 7.62×54mmR) bottlenecked, rimmed centerfire rifle
cartridges still in common use today. Most of the bottleneck rimmed
cartridges of the late 1880s and 1890s fell into disuse by the end of
the First World War.
Commercial ammunition for weapons chambered in
.303 British is readily
available, as the cartridge is still manufactured by major producers
such as Remington, Federal, Winchester, Sellier & Bellot, Prvi
Partizan and Wolf. Commercially produced ammunition is widely
available in various full metal jacket bullet, soft point, hollow
point, flat-based and boat tail designs—both spitzer and
Reloading equipment and ammunition components are also manufactured by
several companies. Dies and other tools for the reloading of .303
British are produced by Forster, Hornady, Lee, Lyman, RCBS, and
Redding. Depending on the bore and bore erosion a reloader may choose
to utilize bullet diameters of .308–.312" with .311" or .312"
diameter bullets being the most common. Bullets specifically produced
and sold for reloading
.303 British are made by Sierra, Hornady,
Speer, Woodleigh, Barnes, and Remington. Where extreme accuracy is
required, the Sierra Matchking 174-grain (11.3 g) HPBT bullet is
a popular choice. Sierra does not advocate use of Matchking brand
bullets for hunting applications. For hunting applications, Sierra
produces the ProHunter in .311" diameter. The increasingly popular
all-copper Barnes TSX is now available in the .311" diameter as a 150
gr projectile which is recommended by Barnes for hunting applications.
With most rifles chambered in
.303 British being of military origin,
success in reloading the caliber depends on the reloader's ability to
compensate for the often loose chamber of the rifle. Reduced charge
loads and neck sizing are two unanimous recommendations from
experienced loaders of
.303 British to newcomers to the caliber. The
classic 174-grain (11.3 g) FMJ bullets are widely available,
though purchasers may wish to check whether or not these feature the
tail-heavy Mk 7 design. In any case other bullet weights are
available, e.g. 150, 160, 170, 180, and 200-grain (13 g), both
for hunting and target purposes.
.303 British cartridge is suitable for all medium-sized game, and
is an excellent choice for whitetail deer and black bear hunting. In
Canada it was a popular moose and deer cartridge when military surplus
rifles were available and cheap; it is still used. The .303 British
can offer very good penetrating ability due to a fast twist rate that
enables it to fire long, heavy bullets with a high sectional density.
Canadian Rangers use it for survival and polar bear protection. In
Canadian Rangers began the process to evaluate rifles
chambered for .308 Winchester, as the Canadian Department of National
Defence expects the currently issued
Lee–Enfield No. 4 rifles will
soon be very difficult if not impossible to maintain due to parts
Firearms chambered for .303 British
Bren light machine gun
Browning Model 1919 machine gun aircraft version
Rifle Mk I through III
Caldwell machine gun
Charlton Automatic Rifle
Globco Mohawk Semi-Auto .303 rifle (modified SVT40 Tokarev)
Hotchkiss .303 Mk I & I*
Huot automatic rifle
McCrudden light machine rifle
Parker Hale Sporter Rifle
Ruger No. 1
Vickers-Berthier light machine gun
Vickers machine gun
Vickers K machine gun
Winchester Model 1895
British military rifles
Caliber conversion sleeve
List of rifle cartridges
Table of handgun and rifle cartridges
7 mm caliber
7 mm caliber (overview of cartridges)
^ ".303 British" (PDF). Accurate Powder. Archived from the original
(PDF) on 30 December 2008.
^ a b c
C.I.P. TDCC datasheet 303 British
SAAMI Drawing 303 British
^ a b David Cushman. "History of the
.303 British Calibre Service
SAAMI Velocity & Pressure Data: Centerfire
15 July 2013 at WebCite
Hornady Handbook of Cartridge Reloading, Rifle-Pistol, Third
Hornady Manufacturing Company, 1980, 1985, p.253-254.
^ Temple, B. A., Identification Manual of the
.303 British Service
Cartridge - No: 1 - BALL AMMUNITION, Don Finlay (Printer 1986), p. 1.
^ a b c Chisholm, Hugh, Encyclopædia Britannica (11th ed.), New York:
The Encyclopædia Britannica Co., Vol. 23, (1911) p. 327
^ a b Sanford, Percy Gerald, Nitro-explosives: a Practical treatise
Concerning the Properties, Manufacture, and Analysis of Nitrated
Substances, London: Crosby Lockwood & Son (1896) pp. 166-173, 179
^ a b c d Walke, Willoughby (Lt.), Lectures on Explosives: A Course of
Lectures Prepared Especially as a Manual and Guide in the Laboratory
of the U.S. Artillery School, J. Wiley & Sons (1897) pp. 336-343
^ a b c d e f Ommundsen, Harcourt, and Robinson, Ernest H., Rifles and
Ammunition Shooting, New York: Funk & Wagnalls Co. (1915), p.
^ A Way Forward in Contemporary Understanding of the 1899 Hague
Declaration on Expanding Bullets - SAdefensejournal.com, 7 October
^ "REJECTED MARK IV. BULLETS".
^ "Dum Dums".
^ 8x50R Lebel (8mm Lebel)
^ "Rifle, Short Magazine Lee–Enfield". The
Website. Retrieved 13 May 2010.
^ "The Deadly
.303 British and The Box O' Truth". Box of Truth
website. [self-published source]
.303 British Cartridge".
^ "The .256 Inch British: A Lost Opportunity" Archived 6 June 2013 at
the Wayback Machine. by Anthony G Williams
^ a b Dunlap, Roy F., Ordnance Went Up Front, Samworth Press (1948),
p. 40. ISBN 978-1-884849-09-1
^ Dunlap, Roy F., Ordnance Went Up Front, Samworth Press (1948),
ISBN 978-1-884849-09-1 p. 40: There appear to have been two
distinct loadings of the Mark VIII cartridge: one small arms expert
serving with the Royal Army Ordnance Corps at Dekheila noted that Mk
VIIIz ammunition he examined had a claimed muzzle velocity of
2,900 ft/s (880 m/s), furthermore, primers on MK VIII fired
cases he examined looked "painted on", normally indicating a pressure
of around 60,000 lbs. per square inch.
^ Temple, B.A. Identification Manual on the
.303 British Service
Cartridge No.1 - Ball Ammunition.
^ Labbett, P.; Mead, P.J.F (1988). "Chapter 5, .303 inch Incendiary,
Explosive and Observing Ammunition". .303 inch: a history of the .303
cartridge in British Service. authors. ISBN 0-9512922-0-X.
Battle of Britain
Battle of Britain - Excerpts from an Historic Despatch by Air
Chief Marshal Sir Hugh Dowding,Flight, 19 September 1946, p323
^ Featherstone-Haugh, JJ. (1973). "Appendix VII, page IV, "British
Military Output WWI"". Home Front - Untold Tales of British Workers
during the Great Wars. OUP.
^ Walter H.B. Smith, Small Arms of the World, Stackpole Publications.
^ Hawks, Chuck. "Matching the Gun to the Game". ChuckHawks.com.
Archived from the original on 20 August 2010. Retrieved 6 September
Here it is – the new Sako rifle for the Canadian Rangers
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"Africa". Sniper Central.
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C.I.P. TDCC datasheet .303 British