Earlier I mentioned this gun at Fort McHenry and misidentified its registry number:
This gun is actually Fort Pitt Foundry number 64. In the same battery, behind it to the left is registry number 57. Fort Pitt cast both guns in 1865. For reasons I elaborated on in the previous post, I feel it proper to call these guns “Type II” due to changes introduced after the first sixty-five 8-inch Rodmans.
After the 15-inch Prototype trials, Thomas J. Rodman modified the basic gun design in order to improve handling. The modifications replaced the older ratchet and pawl elevating system with a socket and bar system. This change required the gun to have zero preponderance on the breech. So the second batch of Rodman rifles had trunnions moved just over an inch to the rear. And to engage the elevating bar, these later 8-inch Rodmans had eight sockets on the breech face.
While the one inch displacement of the trunnions is difficult to ascertain, the presence of squared sockets on the breech is a clear indication of a Type II 8-inch Rodman.
Markings for these guns followed the established U.S. Army practice. In the photo below, those read: 8480 lbs. // S.C.L. // * // 1865 // Fort Pitt PA. // * // No. 57.
Translated, this gun weighed 8480 pounds when inspected by Stephen C. Lyford in 1865 and assigned Fort Pitt registry number 57.
Its mate, also inspected by Lyford, differs only in weight. Number 64 was lighter at 8440 pounds.
These two guns were among a production run of 100 produced by Fort Pitt between May 1863 and August 1865. The Seyfert, McManus & Company, operating the Scott Foundry in Reading, Pennsylvania, delivered forty-eight from July 1864 to June 1865. Cyrus Alger delivered no 8-inch Rodmans despite having open orders for the weapons. Including the sixty-five 8-inch Type I Rodmans from Fort Pitt and West Point, all told the Army received 213 Rodmans in this caliber.
So after rushing the first version of the 8-inch Rodman into production at the onset of war, the Army curtailed purchases within the first year. Production resumed in the middle of the war. However deliveries of the 8-inch caliber never reached that of the 10- or 15-inch Rodmans.
Ordnance tallies in 1872 mentioned a total of 197 of the 8-inch Rodmans in arsenals and forts around the country. By 1891 the fourth edition of the Manual of Heavy Artillery rated the 8-inch Rodman as in service, but not of the system – perhaps a delicate way of saying the Army had a lot of obsolete guns in service.
To the Sound of the Guns 
We have an 8″ Rodman gun (I believe) located in our cemetery here in Michigan dedicated in 1897. On the top end of the barrel is 18 S.O.L. -S.McM&Co. The bottom reads 8465 Lbs 1864. Can you offer more information of the history of this gun and how it could have made the trip all the way to Michigan.
In most cases, the cannon such as the Rodman you mention, were allocated by the War Department to veterans organizations upon request for memorial purposes. Good to hear the cannon still hold a prominent place honoring the men who served our country. In some unfortunately cases I know of, when the veterans organizations gradually lost members, the local communities forgot why those old hunks of iron were there.
Thank you Craig, We are currently doing a restoration project of our cemetery, which includes a 450 crypt community mausoleum built in 1921. We have secured funding to begin a memorial plaza which will include the names of the 62 GAR veterans buried here and relocating the cannon onto a new base in the plaza. I want to provide the history of our cannon, how it came to be here and how rare these are (my research indicates that 197 8″ Rodmans existed in the US arsenal in 1871).