The M712 Copperhead is a 155 mm caliber cannon-launched guided projectile. It is a fin-stabilized, terminally laser guided, explosive shell intended to engage hard point targets such as tanks, self-propelled howitzers or other high-value targets. It may be fired from different artillery pieces, such as the M114, M109, M198, M777 and CAESAR howitzers. The projectile has a minimum range of 3 km (1.9 mi) and a maximum range of 16 km (9.9 mi).

155 mm is a NATO-standard artillery shell caliber that is used in many field guns, howitzers, and gun-howitzers. It is defined in AOP-29 part 1 with reference to STANAG 4425.