The M110 155mm Projectile is an

artillery shell A shell, in a military context, is a projectile whose payload contains an explosive, incendiary, or other chemical filling. Originally it was called a bombshell, but "shell" has come to be unambiguous in a military context. Modern usage ...

used by the

U.S. Army The United States Army (USA) is the land service branch of the United States Armed Forces. It is one of the eight U.S. uniformed services, and is designated as the Army of the United States in the U.S. Constitution.Article II, section 2, cl ...

and U.S. Marine Corps. The M110 was originally designed as a

chemical A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemical substance cannot be separated into its constituent elements by physical separation methods, i.e., wi ...

artillery round to deliver

blister agent A blister agent (or vesicant), is a chemical compound that causes severe skin, eye and mucosal pain and irritation. They are named for their ability to cause severe chemical burns, resulting in painful water blisters on the bodies of those affe ...

s via howitzer as a replacement for the World War I-era 75mm chemical projectiles. The design was later repurposed as a

white phosphorus Elemental phosphorus can exist in several allotropes, the most common of which are white and red solids. Solid violet and black allotropes are also known. Gaseous phosphorus exists as diphosphorus and atomic phosphorus. White phosphorus White ...

smoke Smoke is a suspension of airborne particulates and gases emitted when a material undergoes combustion or pyrolysis, together with the quantity of air that is entrained or otherwise mixed into the mass. It is commonly an unwanted by-product ...

round for marking, signaling, and screening purposes. The

variants of the shell also have a secondary, incendiary effect.

Original design

Officially designated Projectile, 155mm howitzer, M110, the original round was a 26.8-inch (68.1 cm), steel shell with a rotating band near its base and a burster rod down its center. The original shell typically contained of Sulfur mustard (H) or distilled sulfur mustard (HD), which would fill the hollow space in the shell. As early as the 1960s, a

version was created under the same designation with of white phosphorus filler. Both versions were designed for employment by the

M114 Howitzer The M114 is a towed howitzer developed and used by the United States Army. It was first produced in 1942 as a medium artillery piece under the designation of 155 mm Howitzer M1. It saw service with the US Army during World War II, the Korean ...

and the

M44 Self-Propelled Howitzer The M44 was an American-made self-propelled 155 mm howitzer based on the M41 Walker Bulldog tank chassis, first introduced in the early 1950s. Flaws in its design prevented it from seeing action in the Korean War, but the type went on to serve i ...

for use as terrain denial (in the case of the mustard-filled versions), target-marking, and obscuration (in the case of the white phosphorus versions.)

Design variants and markings

M110

The original version of the shell came in two variations, one filled with mustard (HD) (Projectile, Gas, Persistent, HD, 155mm Howitzer, M110) and one filled with white phosphorus (WP) (Projectile, Smoke, WP, 155mm Gun, M110). To distinguish between the two, the HD versions were gray marked with two, horizontal, green bands, like most other

artillery shells. The WP versions were gray with a single, horizontal, yellow band, as is standard for military smoke munitions. Both versions are now considered obsolete, with the WP version seeing updated versions in later incarnations of the shell. The HD version has not been produced since the 1960s and was never used in combat. Remaining stockpiles of the HD version are in the process of being destroyed in accordance with the 1997 Chemical Weapons Convention.

M110A1

The first upgrade to the M110 shell is only slightly modified from the original, maintaining the

filler weight of the original with slight modifications to the release mechanisms to make the shell more reliable. It is primarily used for

signaling In signal processing, a signal is a function that conveys information about a phenomenon. Any quantity that can vary over space or time can be used as a signal to share messages between observers. The ''IEEE Transactions on Signal Processing'' ...

and small-scale

screening Screening may refer to: * Screening cultures, a type a medical test that is done to find an infection * Screening (economics), a strategy of combating adverse selection (includes sorting resumes to select employees) * Screening (environmental), a ...

missions. The M110A1 is gray with a single, yellow, horizontal band, which is standard for military smoke munitions.

M110A2

The second upgrade to the M110 shell is more dramatically modified from the other two variants with thinner casing to increase the amount of filler that can be placed in the shell. The M110A2 contains of

, which increases the duration of the

it produces. This change makes the M110A2 ideal for target marking and large-scale obscuration missions. The M110A2 is gray with a single, yellow, horizontal band, which is standard for military smoke munitions.

Similar projectiles

* M104 155mm Projectile * M121 155mm Projectile *

M687 155 mm Projectile The M687 was an American 155 mm binary sarin chemical artillery shell. The design was standardized in 1976 and production began on December 16, 1987 at Pine Bluff Arsenal, Pine Bluff, Arkansas. Production was halted three years later, following ...

References

{{U.S. chemical weapons 155mm artillery shells Chemical weapon delivery systems Chemical weapons of the United States