.30-40 Krag

The cartridge was also used in the M1893, M1895, M1897, and M1900 Gatling guns.

• Name —.30-40 Krag (originally.30 U.S.) • Origin — United States • Type — Rifle • Service — 1892–1903 • Used By — United States • Design Date — early 1890s • Production Date — 1892–present • Case Type — Rimmed, bottleneck • Bullet —.308 • Land —.301 • Neck —.338 • Shoulder —.423 • Base —.457 • Rim Dia —.545 • Rim Thick —.064 • Case Length — 2.314 • Length — 3.089 • Case Capacity — 58.0 • Max Pressure — 47137 • Pressure Method — C.I.P. • Pressure Method2 — SAAMI • Max Cup — 40,000 • Bw1 — 100 • Btype1 — SP • Vel1 — 2898 • En1 — 1865 • Bw2 — 130 • Btype2 — HP • Vel2 — 2746 • En2 — 2177 • Bw3 — 150 • Btype3 — Nos Part • Vel3 — 2575 • En3 — 2209 • Bw4 — 180 • Btype4 — SP • Vel4 — 2276 • En4 — 2071 • Bw5 — 200 • Btype5 — RN • Vel5 — 1974 • En5 — 1731 • Balsrc — Hodgdon

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. After a brief experiment with a 230-grain bullet loading, the.30 Army loading was standardized in 1894 using a 220 gr metal-jacketed round-nose bullet with 40 gr of nitrocellulose powder. This loading developed a maximum velocity of 2000 ft/s in the 30 in barrel of the Krag rifle, and 1960 ft/s in the 22 in 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. Army, it retained the "caliber-charge" naming system of earlier black powder cartridges, i.e. a.30-caliber bullet propelled by 40 gr 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.

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 owned by Colorado coal miner John Plute, was used to shoot a world-record Rocky Mountain elk near Crested Butte, Colorado. Although Plute never lived to see the record, he gave the antlers to a bar called the Elk Saloon in 1915 to pay his bar tab and died in 1922, 40 years before the record was declared. The massive 6x7 point set of antlers was mounted on the wall until the owner died in 1948 and it was bought by new owners, the antlers remained in the bar for another decade when an experienced elk hunter noticed their impressive size, he suggested to the owners that they get them measured and scored, as they could have a record rack on their hands. The owners then requested an official score sheet from the Boone and Crockett Club, after scoring the antlers and sending the card back the club didn't believe the results, as it was much larger than the current record at the time. So, the owners asked a Colorado game warden to measure the antlers, and the club disbelieved his measurements as well. The club said they would only publish the results if they could examine the antlers in person, so in 1962 the antlers were shipped to their headquarters in New York. The club measured the antlers at being five feet wide and the base measured a foot around, they declared it a world record which stood from 1962 until 1998 when another elk beat it by only quarter of an inch.

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 2200 ft/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 2000 ft/s specification.