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.30-40 Krag

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.30-40 Krag
TypeRifle
Place of originUnited States
Service history
In service1892–1903
Used byUnited States
Production history
Designedearly 1890s
Produced1892–present
Specifications
Case typeRimmed, bottleneck
Bullet diameter.308 in (7.8 mm)
Land diameter.301 in (7.6 mm)
Neck diameter.338 in (8.6 mm)
Shoulder diameter.423 in (10.7 mm)
Base diameter.457 in (11.6 mm)
Rim diameter.545 in (13.8 mm)
Rim thickness.064 in (1.6 mm)
Case length2.314 in (58.8 mm)
Overall length3.089 in (78.5 mm)
Case capacity58.0 gr H2O (3.76 cm3)
Maximum pressure (C.I.P.)47,137 psi (325.00 MPa)
Maximum CUP40,000[1] CUP
Ballistic performance
Bullet mass/type Velocity Energy
100 gr (6 g) SP 2,898 ft/s (883 m/s) 1,865 ft⋅lbf (2,529 J)
130 gr (8 g) HP 2,746 ft/s (837 m/s) 2,177 ft⋅lbf (2,952 J)
150 gr (10 g) Nos Part 2,575 ft/s (785 m/s) 2,209 ft⋅lbf (2,995 J)
180 gr (12 g) SP 2,276 ft/s (694 m/s) 2,071 ft⋅lbf (2,808 J)
200 gr (13 g) RN 1,974 ft/s (602 m/s) 1,731 ft⋅lbf (2,347 J)
Source(s): Hodgdon [2]

The .30-40 Krag, also known as the .30 U.S. and .30 Army, was a rifle cartridge developed in the early 1890s to provide the U.S. armed forces with a smokeless powder cartridge suited for use with modern small-bore repeating rifles to be selected in the 1892 small arm trials. Since the cartridge it was replacing was the .45-70 Government, the new cartridge was considered small-bore at the time. The rifle ultimately selected for use by the Army was the Krag–Jørgensen, formally adopted as the M1892 Springfield. The cartridge was also used in the M1893, M1895, M1897, and M1900 Gatling guns.[3][4][5][6]

History and development

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Though the U.S. Navy and Marine Corps had adopted limited numbers of smokeless powder and bolt-action rifles, the .30-40 was the first cartridge adopted by the US Army that was designed from the outset for smokeless powder. It was patterned after .303 British, to which it is very similar geometrically.[7] After a brief experiment with a 230-grain bullet loading, the .30 Army loading was standardized in 1894 using a 220-grain (14 g) metal-jacketed round-nose bullet with 40 gr (2.6 g) of nitrocellulose powder. This loading developed a maximum velocity of 2,000 ft/s (610 m/s) in the 30-inch (760 mm) barrel of the Krag rifle,[8] and 1,960 ft/s (600 m/s) in the 22-inch (560 mm) barrel of the Krag carbine.

Due to its dimensional similarities .303 brass can be annealed and pressed into .30-40 dimensions in a full-length sizing die. A converted .303 case will turn out ~2 mm shorter than a factory new .30-40 case, but it is still a viable option for handloaders when new factory brass is scarce.

The rimmed .30-40 round was also known as .30 Army or .30 U.S. Although the .30-40 Krag was the first smokeless powder round adopted by the U.S. military, it retained the "caliber-charge" naming system of earlier black powder cartridges, i.e. a .30-caliber bullet propelled by 40 grains (2.6 g) of smokeless powder. The first use of a smokeless powder round by Winchester was a single shot in 30-40, and it was one of only three rounds for which the 1895 Winchester lever action, introduced in 1896, was originally chambered.[9]

From the outset, the .30-40 cartridge proved popular for hunting and was chambered in a variety of firearms. In 1899, a Krag in .30-40 caliber was used to shoot the world-record Rocky Mountain elk. The record stood until the latter half of the 20th century.

In October 1899, after reviewing the experiences of the Spanish–American War, U.S. Army ordnance authorities developed a new loading for the .30 Army used in the Krag rifle, in an attempt to match the ballistics of the 7×57mm Mauser cartridge employed by Spanish forces in that conflict. The new loading increased the muzzle velocity in the rifle version of the Krag to 2,200 ft/s (670 m/s) at 45,000 psi. However, once the new loading was issued, reports of cracked locking lugs on service Krags began to surface. In March 1900, the remaining stocks of this ammunition (some 3.5 million rounds) were returned to the arsenals, broken down, and reloaded back to the original 2,000 ft/s (610 m/s) specification.[citation needed]

In 1903, after recommendations from the infantry Small Arms Board, the U.S. Army formally adopted a higher-velocity .30-caliber replacement for the .30-40 or .30 Army cartridge. The new cartridge was designated by its year of adoption, the .30-03.[citation needed]

A replica of the McKeever-pattern .30 US Army cartridge case

See also

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References

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  1. ^ Saami pressures. (n.d.). Retrieved May 3, 2023, from https://leverguns.com/articles/saami_pressures.htm
  2. ^ ".30-40 data at Hodgdon Online". Archived from the original on 2007-11-11. Retrieved 2007-08-01.
  3. ^ Laststandonzombieisland. (2020, February 7). Great War Gatling Guns?. laststandonzombieisland. https://laststandonzombieisland.com/2020/02/07/great-war-gatling-guns/
  4. ^ Association, N. R. (n.d.). Men and guns of the 1900 China relief expedition. An Official Journal Of The NRA. https://www.americanrifleman.org/content/men-and-guns-of-the-1900-china-relief-expedition/
  5. ^ Colt 1897 gatling gun rifle 30-40. Rock Island Auction Company. (n.d.). https://www.rockislandauction.com/detail/61/1270/colt-1897-gatling-gun-rifle-3040
  6. ^ Colt U.S. navy mark II model 1900 gatling gun with carriage. Rock Island Auction Company. (n.d.-b). https://www.rockislandauction.com/detail/83/1219/colt-us-navy-mark-ii-model-1900-gatling-gun-with-carriage
  7. ^ "A Tale of Three .30s". 7 March 2019.
  8. ^ Johnson, Melvin M. Jr. (1944). Rifles and Machine Guns. New York: William Morrow & Company. p. 384.
  9. ^ History of Winchester Firearms, 1866–1992, Thomas Henshaw, p 44-45
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