.280 British

From Wikipedia, the free encyclopedia

The .280 British, (also known as 7 mm NATO, .280/30, .280 Enfield, .280 NATO, 7 mm FN Short, 7x43 mm) later designated "7 mm MK1Z", was an experimental intermediate rifle cartridge designed by the British Army in the late 1940s (later with help from Fabrique Nationale in Belgium) and the Canadian Army). The .280 British was tested in a variety of rifles and machineguns including the EM-2, Lee-Enfield, FN FAL, Bren, M1 Garand and Taden gun. Despite its success as an intermediate cartridge, the .280 British was not considered powerful enough by the US Army and several variants of the .280 British were created in an attempt to appease the US Army. The US Army would continue to reject these variants, ultimately adopting the 7.62×51 NATO which forced NATO to do the same.

[edit] History

After the end of World War, the British, having encountered new assault rifle cartridges such as the 7.92 "Kurz" on the battlefield, set about replacing their venerable .303. Their goal was to create a cartridge that would replace all small arms in .303 including the Bren, the No.4 rifle and the crew served Vickers with a cartridge suitable for a "light rifle". Thus the cartridge had to demonstrate ballistic performance equal to that of a full powered rifle round and yet exhibit as little recoil and blast as possible. After extensive tests by the "Ideal Cartridge Panel" in 1945, the British decided upon two 7 mm cartridges – the .270 and the .276. In order to focus their efforts, the British ceased research on the .270 and concentrated their efforts on the .276. The .276 was later renamed the .280 even though no dimensions were changed. To add additional confusion the .280 actually has a bullet with a diameter of .284 inches. (The .276 is the measurement of the distance between the rifling lands in the barrel.) Recoil was calculated to be a little under half of the .303. Long range performance actually surpassed that of the .303, and shooters reported that it was much more comfortable to fire with the reduced recoil and reduced blast. It seemed that the British had accomplished their goals. They were soon eager to demonstrate the cartridge to the NATO allies.

However it was not meant to be. Despite interest from the Belgians (FN would later produced the .280 in quantity and help improve it) and the Canadians, the Americans were not at all interested, claiming they would not adopt a caliber under .30. The British attempted to appease the American biases, first with small changes such as changing the rim diameter of the .280 to the size of the .30-06 (resulting in the .280/30 cartridge which was produced in large numbers) and when the .280/30 was outright rejected by the Americans as being too weak with too great a drop in trajectory, the British and Belgians made large changes to the cartridges. These resulted in several different variations, one was just a .280/30 with the bullet seated less deeply so more powder would be put in the case, another was a T65 cartridge case (the T65 would later be the 7.62x51 NATO) necked down to 7 mm. In the end the different cartridges the British and the Belgians came up with fired 140 grain bullets at around 2700 to 2800 FPS, but at a much greater blast and recoil than the .280/30, which defeated the intentions of the initial .280 venture. Unsatisfied with the US Army dragging its feet on the issue, in 1951 the British adopted the EM-2 and the .280/30 as their primary rifle and ammunition with the .280/30 being redesignated as the "7 mm MK1Z". However, this effort was all in vain, and the Americans unilaterally adopted the T65, later to be designated the 7.62x51 NATO.

The 7 mm, EM-2 and Taden gun projects were abandoned soon after by Winston Churchill, who desired to have commonality between the NATO countries. Small amounts of .280 would be produced in the 1960s for various small arms trials. With the American recognition that the 7.62x51 NATO was too powerful a cartridge (and the subsequent change to 5.56x45 NATO) , the .280 concept proved to have been a sound one and ahead of its time.

[edit] Specifications

Various .280 Ball Cartridges. Orange cased cartridge is made out of aluminium.

Types of bullets and colors of tips:

• AP (130 grains)
• API (130 grains): black
• Ball (130–140 grains): plain (unmarked), green, pink, yellow, brown
• Observation (130 grains) (6 grains WP): red
• Tracer (130 grains): white

Note: Most cartridges have been observed with a purple annulus. Several experimental cartridge cases were made out aluminium and are of various colors including orange.

Known manufacturers:

• Radway Green
• Fabrique Nationale
• Kynoch

[edit] Performance

The following comparisons are excerpts from a manual published by the "Small Arms Group Armament Design Establishment" from the Ministry of Supply^[1]:

[edit] Variants

• .270: Designed at the same time as the .280. It has a slightly smaller bullet diameter of .279 inches (versus .284 for the .280) but a lighter bullet (93 to 100 grains) with a greater muzzle velocity (2750–2800 fps), longer case (1.8 inches) and shorter OAL (2.45 inches). Research was abandoned in 1948.
• 7 mm "Optimum": The original .280 round with the bullet seated less deeply, giving an OAL of 2.6 inches.
• 7 mm "High Velocity": Longer case (1.95 inches), with an OAL of 2.79 inches. Similar 140 grain bullet fired at 2750 FPS.
• 7 mm "Compromise" (aka T65/7 mm): Necked down T65 (7.62x51 NATO) to 7 mm. Case length 2 inches, OAL 2.8 inches, similar 140 grain bullet fired at 2800 ft/s.
• 7 mm "Second Optimum" (7x49 mm) : Designed by FN. Also known as the 7 mm "Medium" and the 7 mm "Liviano". FN would later sell FAL rifles chambered in this caliber along with a sizeable amount of ammuition to Venezuela. Longer case (1.935 inches) with an OAL of 2.78 inches. 140 grain bullet fired at 2755 ft/s.
• 6.25 mm (6.25x43 mm): A British experimental cartridge designed during the early 1970s, using the .280/30 as a parent case, which was necked down to fit a smaller bullet.

[edit] Comparable cartridges

From left to right: 6 mm SAW, 6.5 Grendel, 6.8 SPC, 7 mm Bench Rest, .280/30 British, 7 mm-08, 7 mm Second Optimum (Liviano), .276 Pedersen, .308x1.75", 7.62x51 NATO.

For .280:

• 7 mm Bench Rest (Wildcat cartridge, at one time produced by Remington Arms)
• .308 x 1.5" "Barnes" (Wildcat)
• .308 x 1.75" and necked down 7 mm variant (Wildcats)

For 7 mm HV, 7 mm Compromise, 7 mm Second Optimum:

• 7 mm-08 Remington

[edit] See also

• 7 mm caliber, other 7 mm cartridges
• 7.92 x 33 mm
• 7.62×51 NATO
• .276 Pedersen
• 6.8 SPC
• 6.5 Grendel
• 5.56 × 45 mm NATO

[edit] References

• Dugelby, Thomas B. (1980). EM2: Concept and Design. Toronto: Collector Grade Publications. 

• Labbett, P; P.J.F Mead. Technical Ammunition Guide: British 7mm Ammunition. 

• Stevens, R. Blake (1993). The FAL rifle. Toronto: Collector Grade Publications. ISBN 0-88935-168-6. 

• Popenker, Maxim; Anthony G. Willams (2005). Assault Rifle. Ramsbury: Crownwood Press Ltd. ISBN 1-86126-700-2. 

[edit] External links

• British Military Cartridges
• CANNON, MACHINE GUNS AND AMMUNITION
• 7.62 NATO Contemporaries
• .280/ 7 X 43mm Dimensions (Spanish)
• Video of the EM-2