Able Annie

Able Annie was my kind of woman. Big, tough, and powerful, she packed a lot of heat. An enormous, unwieldy cannon, Able Annie and her kin could fire a sixteen kiloton nuclear projectile,

Able Annie, fort Sill (photo courtesy of tr4br)

Able Annie, fort Sill (photo courtesy of tr4br)

about one and a half times the yield of Little Boy, about fifteen miles. While Little Boy, the Hiroshima Bomb, was rated fifteen kilotons it significantly under-yielded.[1] Annie was test fired once in Nevada back in 1953 and the show she gave earned her the nickname Atomic Annie. Her big moment at the Nevada Proving Grounds was immediately followed by retirement. According to the Department of Energy, DOE, twenty cannons were eventually manufactured; most were deployed to West Germany, six to Okinawa, and one may have been sent to Korea. Of those, four remain and are on display. The original Atomic Annie is in the Fort Sill Museum;[2] three others can be seen at the National Atomic Museum, Albuquerque, New Mexico;[3] Fort Riley, Kansas,[4] and Aberdeen Proving Ground, Maryland.[5] Atomic Annie was an anachronism in her own time.

Atomic Annie’s ancestry dates back to 1944 when the Army determined it needed a tactical 240 mm cannon for use on a battlefield or in a specific theater, which are defined operations areas under local military command. The Army craved exceptionally big cannons that could be set up quickly without having to move large quantities of dirt to emplace it.  Once nuclear weapons were proved up, the Army modified the original specifications to 280 mm to accommodate the W-9 nuclear shell (the W-9 is a modification of a nuclear bomb design, the TX8). The Army wanted a tactical nuke.

The subject of whether or not a nuclear weapon is tactical or strategic creates endless hours of debate amongst military historians, students, and enthusiasts who have nothing better to do. Days, weeks and months of negotiation time have been spent at treaty tables in Geneva considering whether this or that nuclear configuration is tactical or strategic. It all comes down to how the package is delivered according to the Air University’s Mark Stout. “… from a practical point of view, a strategic nuclear weapon is…well, it’s one thats delivered strategically. That means delivered via ICBMs, SLBMs, or heavy bombers. Tactical nuclear weapons, it follows, are those that are delivered using battlefield-type delivery systems over battlefield-type distances. However, since the size of a battlefield can vary greatly all we can really say is that they are not strategically-delivered.”[6] You will notice that the Navy is left out of this discussion. In 1991, nukes were removed from surface ships.[7] Some submarines carry nukes that are delivered on the sharp end of a missile. Are they tactical? Yes. Are they strategic? Yes. A nasty little problem that is resolved on a case-by-case basis.

By May 1953, Atomic Annie had been manufactured, delivered, and checked out at the Aberdeen Proving Grounds in Maryland. The Army had also successfully test fired several conventional artillery rounds. She was prepared and shipped by rail to Nellis AFB in Nevada for her participation in the Grable event. Meanwhile at the AEC’s Nevada Proving Grounds, Operation Upshot-Knothole was well underway. A series of eleven nuclear tests conducted between March 17, 1953 and June 4, 1953, Operation Upshot-Knothole was designed specifically “test nuclear devices for possible inclusion in the U.S. arsenal, to improve military tactics, equipment, and training, and to study civil defense needs.”[8] The nuclear cannon, Atomic Annie, was the tenth shot of the eleven shot series and its codename was Grable.

In early May, 1953, Atomic Annie and one other nuclear cannon were placed on their specially designed Kenworth transports and made ready for the trip. The two cannons were considered a

The Kenworth transporters

The Kenworth transporters

battery. Each cannon was accompanied by several vehicles and tenders. The Kenworth vehicle used the same techniques as a large fire department ladder truck; two cabs, each with its own motive power. Beginning in 1950, the Kenworth Motor Truck Company manufactured  33 Front and 33 Rear trucks; each powered by a Continental AO-895-4 six-cylinder engine, with a maximum output of 375 hp and a top speed of 45 mph. The front Truck weighed 19 tons and the rear truck 18 tons.[9] Once the gun was loaded, the caravan arrangement weighed a whopping 84 tons. The convoy must have assumed a parade like atmosphere as it left Nellis en route north to the Nevada Proving Grounds. The word is people gathered along the route like a flash audience.

The Grable shot at 8:30 a.m. on May 25, 1953 was the test firing of the nuclear cannon nicknamed Atomic Annie. The projectile detonated 524 feet above Area 5, Frenchman Flat. The mushroom

Able Annie, the Grable event, May 25, 1953. Smoke trails to the right are from rockets carrying photographic devices used to measure the shock waves created by the blast. Note the 'double mushroom'. (Photo courtesy of National Nuclear Security Administration / Nevada Site Office)

Able Annie, the Grable event, May 25, 1953. Smoke trails to the right are from rockets carrying photographic devices used to measure the shock waves created by the blast. Note the ‘double mushroom’. (Photo courtesy of National Nuclear Security Administration / Nevada Site Office)

cloud from the Grable event was double-headed and dramatic. While the cannon itself was huge,the gun was so well balanced, it could be aimed without the use of hydraulics. The nuke was a W-9, 280 mm tactical nuclear weapon. Physically imposing, the shell was eleven inches in diameter (279.4mm) and fifty four and a third inches long; it weighed about 800 pounds with a range of about fifteen miles.  Between April 1952 and November 1953 about eighty W-9s were manufactured. In 1957, the W-9 was replaced by the Mark 19, which was two hundred pounds lighter with a range of about nineteen miles. The Mark 19 ended its service life in 1963.[10]  Both the W-9 and the Mark 19 are gun type nukes, which generally rely on a cylinder shaped device within which the initial reaction is controlled. The reaction is initiated by shooting a uranium 235 hollow bullet (to keep it sub-critical) into a uranium spike target (also sub-critical) using cordite as the accelerant. Once the two made contact, the nuke went critical so timing was everything. Even with the increased range, the exposure to the detail operating the cannon would have been extreme. Do not believe the propaganda to the contrary.

According to the DTRA Fact Sheet, about 650 DoD personnel participated in the Grable event. Simulations of bridges and other infrastructure were constructed at and around ground zero to judge the effects of the test shot. Sheep were used to simulate human effects from the shot. (See Footnote 8)

More than 2,600 exercise troops and over 700 observers participated in GRABLE. Observers, including members of each of the armed services, witnessed the shot from trenches 4,570 meters west of ground zero. After the shot, observers were to inspect the equipment display area, but because of a dust storm, they were unable to approach closer than 1,370 meters to ground zero. 

After observing the shot with other Desert Rock participants, the exercise troops were to attack two objectives located 2,400 meters southeast of ground zero and 2,800 meters east-southeast of ground zero. High winds and dust forced the troops to turn back about an hour after the attack began, although some troops did approach as close as 700 meters to the south of ground zero and were subsequently able to view the equipment display up to 450 meters from ground zero. 

For the damage effects evaluation at GRABLE, the 412th Engineer Construction Battalion excavated trenches, bunkers, and foxholes and constructed sections of bridging in the display area southeast of ground zero. The 3623rd Ordnance Company also placed military equipment in the area. Army personnel placed sheep and dosimetry instruments in these fortifications for use in medical and shielding evaluations. After the shot, engineer, ordnance, chemical, medical, and quartermaster teams evaluated the damage to equipment, animals, and fortifications. A veterinary officer and technician evaluated the effects of the detonation on the sheep, and a chemical team retrieved dosimetry instruments.

Why was the nuclear cannon ever considered? Times were different during the Cold War and nuclear weapons were new and exotic. All of the military services were looking at how tactical nukes

Davy Crockett, King of the Wild Frontier

Davy Crockett, King of the Wild Frontier

might be used in battle. Atomic Annie and her ilk, like Davy Crockett, a tactical nuclear recoilless gun, were among the ideas that worked clumsily for a short time. According to the Federation of American Scientists, “These scenarios often seemed like nuclear battles because the weapons would be used to blow up troops, bridges or ships much like non-nuclear weapons. Such “tactical” uses were seen by some as a means to avoid escalation to use of strategic nuclear weapons, while others believed that any nuclear use would automatically escalate to strategic nuclear war.”[11] The Soviets, upon seeing Atomic Annie, wanted one of their very own-The Cold War my daddy is bigger than your daddy game-so they developed the Objeckt 271.

The Russians and President Obama remain committed to keeping tactical nukes in the arsenal. The US is worried about China’s actions and the Russians are worried about US actions. The US is considering a policy of absorbing a first nuclear strike without responding. Not a good idea in my book, but, then again, I am a Cold War warrior. The tactical nukes of yesteryear demanded that the troops run as far and as fast as they could away from where they were pointed after firing. While it was a poor plan, it was the best the military could muster. Today’s tactical nukes go farther and faster before detonation and are, perhaps, more survivable.

[Author’s note: There are two videos well worth watching. Trinity and Beyond, a documentary produced in 1995 is about 98 minutes long and can be viewed at .  The second is from the Nuclear Vault. It is about ten minutes long and deals solely with Atomic Annie; The 280 MM Gun At The Nevada Proving Ground ]

[1] Physics Today; Henry E. Heatherly; University of Louisiana; February 2003  page 14; Hiroshima Bomb’s Explosive Yield Less than Reported;

[2] U.S. Army Field Artillery and Fort Sill Museum;

[3] The National Museum of Nuclear Science History;

[4] Roadside America; Atomic Cannon;

[5] Army Ordnance Museum;

[6] The Wright Stuff; Air University;  13 May 2010; Mark Stout;

[8] Defense Threat Reduction Agency; Fact Sheet; July 2007;

[9] The Atomic Cannon Cold War Deterrent;

[10] US Nuclear Weapons the Secret History; Chuck Hansen;

[11] Federation of American Scientists; Special Report No 3; May 2012; Non-Strategic Nuclear; HANS M. KRISTENSEN;

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