I found a listing that shows six steel 3-inch rifles produced by the Singer-Nimick Company. Number 6 is at Gettysburg. Numbers 1 and 5 are on the Chickamauga Battlefield. The location of the other three is unknown.
I read that two of these where captured by Forrest at Lexington TN in Dec 1862. These two became the famous Bull Pups of Morton's Battery.
The two at Chickamauga are not where Morton's Battery saw action but are instead placed where Union batteries were located along side iron 3-inch ordinance rifles (which look practically identical).
It seems 3-inch ordinance rifles are sometimes referred to as "Rodmans", perhaps due to their shape. As far as I know, Rodman guns were large-bore hollow-cast guns. I wonder if only the steel rifles were referred to as Rodmans or if that name was mis-applied to all 3-inch ordinance rifles. Were the steel rifles hollow-cast? The wrought iron 3-inch ordinance rifles were not.
Two 3-inch "Rodmans" were captured by Forrest at Brice's Crossroads. Were these also steel?
From other reading, it is questionable whether the two steel Singer-Nimick 3-inch rifles at Chickamauga are in fact the two Bull Pups captured at Lexington TN. They are certainly two of the six cast by Singer-Nimick but there are conflicting stories on what happened to Morton's guns at the end of the war and how these two got to Chickamauga.
I'm a real novice on artillery (and most everything else for that matter). Any insight on these steel rifles and Morton's Bull Pups would be appreciated. I have pictures of the two at Chickamauga I'll gladly share -- email me a email@example.com. Our webmaster Jim Martin and I visited the battlefield on the 150th anniversary of when our ggg grandfather Volney F. Willoughby was killed (Co. A, 5th GA Inf) and coincidentally Capt John Morton's 21st birthday -- Sept. 19, 1863.