By Jenn Jett, Museum Specialist
A 155m howitzer fires a Copperhead round during development and testing at White Sands Missile Range. The Copperhead follows a trajectory similar to conventional artillery rounds until its descent phase. 
A Copperhead round a split second before impact on an M60 Patton tank target. The Copperhead round consists of a shaped charge with 14.75lbs of Composition B, an explosive mixture of TNT and RDX. 
A split second after impact and detonation. Due to its accuracy and explosive force, the Copperhead was used on enemy armor, observation positions, fortified positions, artillery positions, and other vehicles. 
A Copperhead round is prepped for firing from a 155mm M109 self-propelled howitzer. The Copperhead can be fired from a variety of different 155mm cannons including the M109, M114, M198, and M777 towed and self-propelled howitzers. 
An artillery crew loads a Copperhead round into their M198 towed howitzer. The M198 was developed, tested, and fielded in 1969 and through the 1970s. It is crewed by 9 artillerymen and is capable of firing at up to 4 rounds per minute. 
A view of an artillery crew from the end of the M198’s barrel. The two Soldiers behind the gun are loading a Copperhead round into the breech. The two Soldiers on either side are adjusting the elevation and lateral firing direction. 
A forward observer uses a tripod mounted G/VLLD laser target designator. The G/VLLD uses an infrared laser, invisible to the naked eye, to acquire range information and illuminate an enemy target. The forward observer relays firing directions to the howitzer crew and keeps the laser trained while the howitzer crew fires the round. The Copperhead’s optical seeker head assembly picks up the laser and directs the guidance system onto target. 
A Copperhead round (top left) a split second before impact on a tank target. The high explosive shaped charged was designed to pierce enemy armor and destroy the target. The accuracy and explosive power also made the Copperhead a perfect option to destroy point positions, clearing the way for friendly forces to move forward. 
The Copperhead’s guidance vanes that maneuvers the round onto target are clearly visible in this silhouette image before impact. As long as the howitzer fires in the general direction of the target, the guidance systems can steer the round during its ballistic trajectory to the illuminated point. The round’s “footprint” is determined by the range, direction, and parabola of the firing ballistics. The footprint determines the probability of the round hitting the illuminated target. The smaller the footprint, the more likely the round is to land on target.
The M712 Copperhead was developed at White Sands Missile Range, New Mexico and first fired in 1972. The Copperhead was developed as a high-explosive, laser-guided, anti-tank projectile that was fired from a standard M114, M777, or other 155mm howitzer and is considered to be the first “smart artillery round,” officially known as a cannon-launched guided projectile (CLGP).
Upon being fired from its howitzer, the Copperhead follows a ballistic or glide trajectory. After it reaches the apex and begins its descent phase, guidance vanes extend from the round and the onboard optical system picks up the laser-illuminated target while the guidance system maneuvers the round onto target. The target is illuminated by a forward observer using a laser target designator (LTD).
It has a large effective range, up to 16km, but several factors limit its use. It has a minimum firing range of 3km to allow the round to maneuver on target and is less effective in heavy cloud cover and in low visibility conditions. Additionally, the forward observer must keep the illumination laser trained on the target until impact, something difficult to do on a moving target or from far away.
Although the round was designed to be used against hard point targets such as tanks and fortifications, the Copperhead was used on enemy artillery, radar, and observation positions in Operation Desert Storm and Operation Iraqi Freedom in 1991 and 2003, respectively.
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