The 3-inch Ordnance Rifle was an extremely accurate rifled cannon.
It was designed by a man named John Griffen who was the superintendent of the Safe Harbor Iron Works located in Pennsylvania.
Although it was initially designed by the Phoenix Iron Company also located in Pennsylvania.
The Phoenix Iron Company was responsible for producing most of the 3 inch rifles used in the Union Army during the war.
This gun was very similar in length to the Parrott rifle and it also fired an elongated shell and it was very accurate up to a mile in distance.
The gun weighed in at around 800 pounds, which made it incredibly easy for the gun crews to handle and transport.
The Confederate army also tried to replicate this gun but they only ever managed to produce a small number of them during the war.