Iran has begun manufacturing a 100mm radar controlled anti-aircraft gun called the Saeer. This new weapon appears to be a copy of the Chinese Type 59, which is in turn is a copy of the late 1940s Russian KS-19. That, in turn, was an improved version of the World War II 85mm anti-aircraft gun. These heavy anti-aircraft guns did a great deal of damage to bombers or any other aircraft that travelled in some kind of formation at high altitudes. Dozens of these guns can create a wall of exploding shells, at a location in the sky that radar indicates enemy aircraft are fast approaching, and unable to fly around. Flying through the sky full of exploding shells (user timer fuzes to detonate the shell at a specific altitude) has become a cinema cliché that is very much based on reality.
Using optical sights, the Type 59 had an effective range of 21 kilometers and max altitude of 15 kilometers (49,000 feet) using a radar (proximity) or timer fuze. The Saeer probably weighs about 11 tons, has a crew of about a dozen and can fire about 15 rounds a minute for short periods. Barrel life is about 3,000 rounds.
During World War II, it took about 3,000 heavy caliber anti-aircraft shells to shoot down one aircraft. It took only a few hundred shells to damage an aircraft. The radar/proximity (exploding when it neared a target) fuze made the big guns more effective, but after World War II, most bomb attacks were by small numbers of jet fighter-bombers coming in individually. Thus it still took several thousand rounds of heavy caliber anti-aircraft shells to bring down an aircraft. This is one reason why anti-aircraft missiles became so popular, and have largely replaced the big funs. Russia stopped using its 100mm anti-aircraft guns in the 1980s.
