DaveSB, Thanks for posting all those great pics! Looks like one heck of a tour. I always wondered what their shop looked like. I own 3 cannons and 1 mortar made by SBR and I have enjoyed their quality and reliability since 1972. Did Jim mention anything about that 10" Seacoast Mortar M1841 shown in your second photo of Reply #3? The lifting lug is on the other side, most likely. I believe they weigh more than 5,000 Lbs. and that they made one for Fort McAllister on the Ogeechee River, south of Savannah, Georgia in the 80s.
The original 10" had an active bit of service there. I was reading Durham's, Fort McAllister recently and was surprised to find out that it shook the walls of the magazine and the Bomb Proofs so violently that they had to drag it almost 100 yards SSE of the fort to a special, solitary emplacement. From here it bombarded the Federal ironclads during the naval attacks of 1863 and Capt. Martin commanding this battery hit several Federal Monitors including the Monitor Nahant upon their decks with shells which he observed had no effect. He had the gun's shells unloaded and sand put in, hoping to make them heavy enough to penetrate the 1" deck armor. There were no Union Navy reports of being "Holed", and reports of frantic repair activity as river water rushed in below decks, so I guess his sand loads did not find a target, after all.
Tracy