JR Potts, AUS 173d AB (Updated: 8/22/2014):
Second Lieutenant Thomas Jackson Rodman was assigned to the Army Ordnance Department at the Allegheny Arsenal in Pittsburgh, Pennsylvania after graduating seventh in his class from West Point in 1841. In 1844, the USS Princeton was one of the most advanced ships of her time - becoming the first screw steam warship fielded by the United States Navy. She was fast-equipped with a 14 foot, 6-blade screw powered by a coal burning boiler. She needed guns that projected power so the Princeton sailed for New York in January of 1844 to receive her two big cannon - named "Peacemaker" and "Oregon".
The Oregon was a 12-inch (300mm) smooth-bore, muzzle-loaded cannon made of wrought iron and could fire a 225-pound (100kg) shot some 5 miles (8 km) using a 50-pound charge of gun powder. Made in England by the Mersey Iron Works, the weapon was sold to the US Navy in 1841. A new built-up construction process was used, this accomplished by arranging iron hoops delivered hot from the forge, around the back of a casted cannon. The process was to allow higher amounts of gun powder to be used to prevent an explosion when firing. The second cannon - the Peacemaker - was made in the United States by Hogg and Delamater of New York and was also a 12-inch muzzle-loader able to match the shot and range of the English-made Oregon. The construction process was different, however, as the Peacemaker did not make use of additional bands for support. The breech end was increased in metal thickness during the casting process itself. The weight of the gun was greatly increased without reducing the flaws experienced in wrought iron cannon construction prior.