The Royal Dutch Army has issued a $44 million contract to Krauss-Maffei to upgrade 180 Leopard-2A5 tanks into Leopard-2A6s. This will include the replacement of the 44-caliber 120mm cannons with new 55-caliber 120mm cannons. (Caliber refers to the length, in this case being 44 or 55 times as long as the diameter.) The extra 1.32m of barrel length will give the guns greater range and penetrating power with the same ammunition. The German Army is having 225 of its own Leopard-2A5s upgraded to Leopard-2A6s by Krauss-Maffei.--Stephen V Cole