Thanks for the extra photos, there's no question this is a 12-pounder Confederate field howitzer by Quinby and Robinson of Memphis. I'd suspect it is the privately-owned piece, if it is being fired. NPS, who owns all the rest, no longer fires original pieces. It has been cleaned, probably chemically, as the normal patina is gone and the surface is quite rough. The registry or foundry number would normally be on the muzzle face but if it is I can't make it out for sure. There were eight of these Q&R specimens known at time of writing of TBG. One was privately owned, and there were two in Des Moines IA, two at Gettysburg, three at Shiloh. The total number of Confed. 12 pdr. field howitzers by all makers, listed in TBG, is 62, although a number are unmarked and "presumed" to be of that model.
