This three-inch ordinance rifle came to Fort Benton sometime after the Civil War, probably during the time it was a military port, 1869-1881. It has remained here since its arrival, and was here during the Indian Wars of 1876-1877. It has seen no action since the Civil War. Fort Benton's mountain howitzer, inside the museum, did see action during the Nez Perce War in 1877.
Designed by the U.S. Ordinance Department in 1861, it has smooth barrel lines, a new concept, rolled wrought iron instead of bronze was used in the barrel to reduce cost and production time. Its carriage is a standard six-pounder field gun type, and could rapidly be changed in case of broken parts.
The three-inch ordinance rifle gained fame in the Confederate Army for its accuracy. "Union gunners could hit the end of a flour barrel at a half mile more often than they missed." During the siege at Richmond, "Yankee gunners with the 3" rifle put shells through the ports of our ramparts at a mile with forbidding regularity.
The muzzle stampings show that this cannon was produced along with 1000 other barrels, at the Phoenix Iron Works in Phoenixville, PA. This particular barrel is no. 799 and was produced in 1864. Its sister cannon is at Gettysburg National Battlefield.