.276 Enfield

Not to be confused with .276 Pedersen.

.276 Enfield
Type	Rifle
Place of origin	United Kingdom
Production history
Designer	Royal Laboratory
Designed	1912
Produced	1912–1916
Specifications
Case type	rimless, bottleneck
Bullet diameter	.284 in (7.2 mm)
Neck diameter	.323 in (8.2 mm)
Shoulder diameter	.460 in (11.7 mm)
Base diameter	.528 in (13.4 mm)
Rim diameter	.521 in (13.2 mm)
Case length	2.35 in (60 mm)
Overall length	3.23 in (82 mm)
Case capacity	72 gr H2O (4.7 cm3)
Primer type	Berdan
Ballistic performance
Bullet weight/type Velocity Energy 165 gr (11 g) 2,800 ft/s (850 m/s) 2,888 ft·lbf (3,916 J)
Source(s): [1]

The .276 Enfield was an experimental military rifle cartridge developed in conjunction with the Pattern 1913 Enfield (P'13) rifle. Development was discontinued by the onset of World War I.

Ballistics

The .276 Enfield was designed with the intent of being more powerful than the .303 British cartridge used in the Lee–Enfield rifles. The Mauser-type action of the Pattern 1913 rifle was very substantial and designed to be stronger than the Lee–Enfield action, to allow for the higher energy .276 cartridge. While the .303 British round has a larger-diameter projectile than the .276 Enfield, the .276 Enfield cartridge case is larger and contains more propellant developing higher chamber pressures and, as such, is more powerful than the .303 British. The .303 Mk VII round, for instance, has a projectile weight of 174 grains and a muzzle velocity of 2,441 ft/s, while the .276 has a projectile weight of 165 grains and a muzzle velocity of 2,785 ft/s. This is partly due to the slimmer bullet of the .276 Enfield, which was more aerodynamic and designed to travel at faster velocities. The .276 Enfield was designed to be similar in size and performance to other large, powerful early 20th century military rifle cartridges, like the 7.92×57mm Mauser, .30-06 Springfield and 7.5×55mm Swiss GP11. The combination of a projectile with a higher sectional density propelled at a higher velocity gave the .276 Enfield better ballistics than the .303 British, and was also rimless to ensure greater reliability in magazine-fed weapons, a problem with the older .303 round. However, due to the approach of WWI, the .276 Enfield was not implemented for military service. Ironically, the SMLE proved to be a superior format for WWI trench warfare.

History

Several developmental versions of ammunition were prepared beginning in 1910 before approximately 1,000 P'13 rifles with 600,000 rounds of RL18000C trials cartridges were distributed to troops in 1913. The troops' trials rifles and ammunition were distributed to the musketry school at Hythe, to one squadron in each of three cavalry regiments, and to one company in each of eight infantry battalions. One of the cavalry squadrons was stationed in South Africa and one of the infantry companies was stationed in Egypt. The remainder of the units were in the United Kingdom. Cartridges were packaged in 5-round stripper clips similar to those used by Mauser and M1903 Springfield rifles. Ball ammunition was loaded with 49.3 grains of cordite behind 165-grain cupronickel-jacketed 1.365 in long spitzer bullets. Drill rounds containing no primer or powder have been reported in two versions. One has a tin-plated case with the standard bullet, and the other has a round-nose wood bullet with an unplated brass case.

The troop trials reported the cartridge produced heavy recoil with undesirable muzzle flash and overheated rifle barrels. Overheating caused excessive barrel wear and some potentially dangerous pressure indications from cartridges pre-heated in hot barrels before firing. Rather than confront continued development of a new cartridge simultaneously with inevitable wartime production problems, the United Kingdom continued manufacturing .303 British caliber Lee–Enfield rifles as the standard military arm through the first world war. Canada, on the other hand, had some experience with the similar .280 Ross cartridge and appears to have taken interest in potential use of the P'13 rifles to arm newly mobilized troops. Canada contracted with Winchester Repeating Arms to manufacture ammunition until more suitable rifles became available for standard issue.

Ammunition is known to have been manufactured by:

• Royal Laboratory (headstamped R^L)
• Kings Norton Metal Company (headstamped KN, some with date 13)
• Greenwood & Batley (headstamped GB or G&B)
• Kynoch (headstamped K)
• Winchester (headstamped WRA Co 8-16)

Subsequent developments

The P'13 rifle design was modified as the Pattern 14 Rifle (P'14) chambered for the .303 British cartridge. Production was initially assigned to Vickers; but tooling was shortly passed to United States manufacturers so Vickers could focus on machine gun production. Remington Arms and Winchester manufactured 1,233,075 P'14 rifles for the United Kingdom in 1915 and 1916. Remington subcontracted the largest share of production to the Baldwin Locomotive Works plant in Eddystone, Pennsylvania. The design was modified again as the M1917 Enfield rifle chambered for the .30-06 Springfield cartridge. Remington, Winchester and Baldwin manufactured 2,193,429 M1917 rifles for the United States. Approximately 75% of the American Expeditionary Forces carried M1917 rifles into combat. Nearly half of these M1917 rifles were sent to the United Kingdom as Lend-Lease in the early days of World War II. Remington modified the design again as the basis of their model 30, 30S, and 720 rifles for civilian production.

The .276 Enfield case was necked up to .303 caliber for various armor-piercing bullet tests conducted in the United Kingdom between 1922 and 1935.

See also

• .275 H&H Magnum
• List of rifle cartridges

External links

• A History of Military Rifle Calibers: The Infantry Magnums, 1902-1914
• .256 and .276 Enfield Experimental Ammunition Trials