The International Metallic Silhouette Shooting Union (IMSSU) is the international organization for metallic silhouette shooting, which was founded in 1992 in response to the fact that rules for metallic silhouette shooting started to diverge around the world.
The European regional body is Association Européenne de Tir sur Silhouettes Métalliques (AETSM), which means European Metallic Silhouette Shooting Association
References
International Metallic Silhouette Shooting Union Wikipedia(Text) CC BY-SA