The .276 Pedersen (7×51mm) round was an experimental 7 mm cartridge developed for the

United States Army The United States Army (USA) is the primary Land warfare, land service branch of the United States Department of Defense. It is designated as the Army of the United States in the United States Constitution.Article II, section 2, clause 1 of th ...

. It was used in the

Pedersen rifle The Pedersen Rifle, officially known in final form as the T1E3 rifle, was a United States semi-automatic rifle designed by John Pedersen that was made in small numbers for testing by the United States Army during the 1920s as part of a program to ...

, later versions of the

Thompson Autorifle The Thompson Autorifle, (also referred to as the Thomoson Model 1923 Autoloading Rifle; and the .30-06 Model 1923 Semi-Automatic Rifle, among others, etc.) was a semi-automatic rifle that used a Blish Lock to delay the action of the weapon. It ...

and early versions of what would become the

M1 Garand The M1 Garand or M1 rifleOfficially designated as U.S. rifle, caliber .30, M1, later simply called Rifle, Caliber .30, M1, also called US Rifle, Cal. .30, M1 is a semi-automatic rifle that was the service rifle of the United States Army, U.S. ...

Summary

Developed in 1923 in the United States, it was intended to replace the

.30-06 Springfield The .30-06 Springfield cartridge (pronounced "thirty- aught-six" ), 7.62×63mm in metric notation, and called the .30 Gov't '06 by Winchester, was introduced to the United States Army in 1906 and later standardized; it remained in military us ...

in new

semi-automatic rifle A semi-automatic rifle is a type of rifle that fires a single round each time the Trigger (firearms), trigger is pulled while automatically loading the next Cartridge (firearms), cartridge. These rifles were developed Pre-World War II, and w ...

s and machine guns. When first recommended for adoption, M1 Garand

rifle A rifle is a long gun, long-barreled firearm designed for accurate shooting and higher stopping power, with a gun barrel, barrel that has a helical or spiralling pattern of grooves (rifling) cut into the bore wall. In keeping with their focus o ...

s were chambered for the .276 Pedersen, which held ten rounds in its unique

en-bloc clip A clip is a device that is used to store multiple rounds of ammunition together as a unit for insertion into the magazine or cylinder of a firearm. This speeds up the process by loading the firearm with multiple rounds simultaneously, rather th ...

s. The .276 Pedersen was a shorter, lighter and lower pressure round than the .30-06, which made the design of an autoloading rifle easier than the long, powerful .30-06. The U.S. Army Chief of Staff Gen.

Douglas MacArthur Douglas MacArthur (26 January 18805 April 1964) was an American general who served as a top commander during World War II and the Korean War, achieving the rank of General of the Army (United States), General of the Army. He served with dis ...

rejected the .276 Pedersen Garand in 1932 after verifying that a .30-06 version was feasible.

History and technical notes

Pedersen's round fired a 0.284-inch (7.22mm) bullet. Comparable to the contemporary Italian 6.5×52mm (0.268 in)

Carcano Carcano, Mannlicher-Carcano, Carcano-Mannlicher, and Mauser-Parravicino, are frequently used names for a series of Italian bolt-action, internal box magazine fed, repeating military rifles and carbines. Introduced in 1891, the rifle was officia ...

or the Japanese 6.5mm (0.264 in)

Arisaka The Arisaka rifle () is a family of Japanese military bolt-action service rifles, which were produced and used since approximately 1897, when it replaced the Murata rifle (, ) family, until the end of World War II in 1945. The most common model ...

, it produced velocities of around 2,400 feet per second (730 m/s) with 140 or 150 grain (9.1 or 9.7 g) projectiles. The case was two inches (51 mm) long with significant taper. Tapered cases simplify the extraction, but require the use of highly curved magazines similar to the Kalashnikov, although for the short magazines of the Pedersen and Garand rifles, this was immaterial. Both waxed and bare cartridges were made for the Pedersen and Garand rifle respectively. An armor-piercing T1 cartridge was developed and presumably a tracer. At the time of its introduction, the .276 Pedersen was a solution to a significant problem. The U.S. Army wanted a general issue autoloading rifle that would fire the .30-06 cartridge, but such a rifle was prohibitively large with existing designs such as the Browning Automatic Rifle and French

Chauchat The Chauchat ("show-sha", ) was the standard light machine gun or "machine rifle" of the French Army during World War I (1914–18). Its official designation was "Fusil Mitrailleur Modele 1915 CSRG" ("Machine Rifle Model 1915 CSRG"). Beginning ...

. A weapon of the same weight as the M1903 needed to fire a smaller cartridge. Pedersen's cartridge was viewed as a compromise as it was underpowered compared to most military rifle cartridges. This decreased recoil energy made possible a reliable, lightweight semi-automatic rifle with existing technology. Despite overcoming these early semi-automatic problems, the Garand was chosen because it did not require the use of lubricated cartridge cases for reliable function. The Garand was originally going to be chambered in the .276 Pedersen, but the logistics of changing all of the infantry's guns (including machine guns) to a new round was judged cost-prohibitive, so the Garand was chambered in .30-06, removing the need for the new cartridge. Immediately after World War II, British designers introduced a series of intermediate-power 7mm cartridges for a different reason than Pedersen. They sought an answer to the Germans' highly successful 7.92mm ''Kurz'' and various studies on the matter. The U.S. stuck with the .30 caliber mostly out of a desire to have a common cartridge between rifle and machine gun combined with the perceived necessity for effectiveness out to 2,000 yards and perforation of intermediate barriers. Development of a shorter .30 round specifically for use in an autoloading rifle began after the war, and resulted in the

7.62×51mm NATO The 7.62×51mm NATO (official NATO nomenclature 7.62 NATO) is a rimless, straight walled, bottlenecked, centerfire rifle cartridge. It is a standard for small arms among NATO countries. First developed in the 1950s, the cartridge had first be ...

, a shorter and slightly lighter round that gave slightly superior ballistics to the .30-06. The British studies on various cartridges culminated in the .280 British cartridge, which shared logistic similarities to the .276 Pedersen in caliber, bullet weight and velocity, but not in range, Ballistic Coefficient or wounding power. Despite the failure to adopt either the .276 Pedersen or later .280 British, the concept of an intermediate power military cartridge of a 6.5 to 7mm diameter was far from dead. Shortly after the 7.62mm NATO cartridge was adopted,

Armalite ArmaLite, or Armalite, is an American small arms engineering company, formed in the early 1950s in Hollywood, California. Many of its products, as conceived by chief designer Eugene Stoner, relied on unique foam-filled fiberglass butt/stock fur ...

submitted their

AR-10 The ArmaLite AR-10 is a 7.62×51mm NATO battle rifle designed by Eugene Stoner in the late 1950s and manufactured by ArmaLite (then a division of the Fairchild (aircraft manufacturer), Fairchild Aircraft Corporation). When first introduced in 1956 ...

for evaluation, the U.S. Army suggested they redesign the gun to fire a .256 caliber projectile. Although this suggestion was fruitless, the Army later engaged in many studies of a 6mm SAW cartridge. They, once again, sought to replace autoloading rifle and machine gun cartridges with one round. Nearly 100 years after the .276 Pedersen introduced the concept of a 7mm infantry round for semi-automatic rifles, on April 19, 2022, the

adopted the .277 Fury (6.8x51mm Common) as the United States Army's general-purpose cartridge, this cartridge features a 7.04 mm bullet in a two-part version of a necked down 7.62x51mm NATO case. It has a stainless steel head and a brass body to withstand the huge increase in pressure required to attain the perforation, wounding and flatness of trajectory to the required ranges. The adoption of this round repudiates the Army's 1923 conclusion about concerning the adoption of the .30 caliber standard (then signified by the rejection of the .276 Pedersen) compared to a .276 caliber round (7mm caliber), and finally returns ballistic performance in front of General Douglas MacArthur's cost-saving decision to scrap a 7mm bullet in favor of military surplus 30-06 ammunition left over from World War One as the primary cartridge to be used in the M1 Garand during World War Two. The new 7-mm .277 Fury round will be deployed both in an infantry battle rifle as well as in a dedicated machine gun and exemplifies the requirement of the much higher chamber pressure, 80-90,000 PSI Vs 55-60,000 PSI in the older ammunition required to attain the demanded ballistic performance with a 7-mm bullet in both weapon systems.

References

*Cartridges of the World. Frank C. Barnes. *Handloader's Manual of Cartridge Conversions. Donnelly + Townsend *Guns. Chris McNab *Book of Combat Arms 2005. Guns and Ammo Magazine

External links

patent
{{DEFAULTSORT:276 Pedersen Pistol and rifle cartridges Experimental cartridges

Summary

History and technical notes

See also

References

External links