Without a projectile it would not recoil much at all, but, as I've learned here many times over what you do with it and the next guy does with it are 2 different things. That cannon will probably out live you by a couple generations but what if a great grand child was to load it to the max with a 1 1/2 lead ball? Better safe then sorry. Some scrap yards have a tool to check which steel is which. If the trunnions are welded that dates it to later then 1881 (probably much later). Just my thoughts.
“I won't be wronged. I won't be insulted. I won't be laid a-hand on. I don't do these things to other people, and I require the same from them.”
― John Wayne "The Shootist"