Iran has been building and using the Raad-2 (a copy of the US Army's M-109A2) for several years, but has just released the first details. The vehicle is made from steel (maximum 20mm thick), not aluminum, and incorporates some parts (e.g., roadwheels) from the T-72 which Iran also builds. This pushes the weight to 36 tons; the M109A2 weighs a mere 25 tons. The Raad-2 has a long 39-caliber barrel, giving it a range of 18,100 meters with standard ammunition and 24,000 meters using base-bleed ammunition. Base-bleed shells have a small burning charge in the rear, which creates a gas pocket behind the shell, effectively making it longer and more streamlined. In theory, Raad-2 could be given a 45-caliber barrel and reach 40,000 meters with special ammunition. Firing rate can be sustained at four rounds per minute, and the barrel has a service life of 5,000 rounds (at the most powerful charge, known as Charge 8). Elevation limits are 75 degrees (highest) to -3 degrees (lowest). There are sights for both direct and indirect fire on top of the turret. The five-man crew includes a driver (who sits at the left front) and four to actually serve the gun. The V84MS diesel engine (borrowed from the T-72) provides 840 horsepower, which gives a power-to-weight ratio of 23hp/ton (quite acceptable for a self-propelled howitzer) and a maximum road speed of 64 kph (roughly 40 miles per hour). Another version of the vehicle, the Raad-2M, uses the 700hp 5TDF engine from the T64 tank, providing a lower ratio and speed.--Stephen V Cole