The Jaivana cannon is the world's biggest wheeled cannon ever made. It is located at the Jaigarh Fort, Jaipur. It was cast in 1720, during the reign of Maharaja Sawai Jai Singh II of Jaipur.
Jaivan rests on a high 4 wheeled carriage. The front wheels are 2.74 m in diameter and the rear wheels are 1.37 m in diameter.
The length of the barrel of the cannon is 20 feet 2 inches and it weighs 50 tons. The circumference near the tip of the barrel is 7 feet 4 inches and that of the rear is 9 feet 4 inches. The barrel has floral design. An elephant rests on the tip of the barrel and a pair of peacocks are carved in the centre. A pair of ducks also decorates the rear of the barrel. The diameter of the bore of the barrel is 11 inches and the thickness of the barrel at the tip is 8-1/2 inches. The thickness gradually increases as one moves towards the rear of the barrel. The two thick rings on the barrel were used for lifting it with the help of a crane which, though incomplete, is still lying in Jaigarh. A 776 mm long elevating screw was used for raising and lowering the barrel. Reportedly, it took four elephants to swivel it around on its axis.
About 100 kg of gun powder fired a shot ball weighing 50 kg.
The uses and range of the cannon and cannonballs vary over different sources. Some say the Jaivana Cannon was only fired once by the Maharajah Jai Singh, as a test-fire in 1720. Others say that it was fired many times, indicated by the fire marks on the inside of the barrel. The most exaggerated myth claims that the it had a range of 40 km with the Maharajah's test fire, other sources say it is 35, 22 and 11 km, although the exact range could perhaps never be determined without adequate scientific computation. Most sources agree that it was fired in the direction of Chaksu, where the impact was said to be so colossal that it formed a depression that has since formed a pond. Cannons always had a water tank beside them, for the gunner to jump into to avoid the massive shock wave. Jaivan's gunner is said to have died on the spot on firing the cannon, before he could jump into water.