The cannon called the 3-inch Ordnance Rifle (also called the 3-inch Wrought Iron Rifle) was an early favorite of the Ordnance Board due to its accuracy. These and other rifled guns were distinguished by their black barrels. About 1,000 were bought during the war. They were made by the Phoenix Iron Works of Phoenixville, Pennsylvania. They were made of wrought iron strips bent on a mandrel then welded together. They were then machined into their final shape. The early prototypes were fired 500 times with no signs of wear. It was accurate and reliable in battle. The Confederacy also produced a 3-inch Ordnance Rifle. But the use of low-grade iron ore and poorer rifling machinery made these guns less reliable.