Iran has developed new base-bleed ammunition to extend the range of its 130mm artillery from the current 27,000m to 37,000m. Iran uses both the Russian M46 towed 130mm howitzer and the Chinese copy of this weapon designated Type-59-1. The new ammunition weighs 35.5kg and contains 3.7kg of TNT. This is a slightly heavier shell with 20% less explosive in it.--Stephen V Cole