1943Mike
as I'm not versed on military ordnance whether from the present or the 19th century but they sure look the part to this modeler.
About 1850, the "bottle shape" barrel shape became the "thing." That, and the Armstrong "wedding cake" patterns with hard steps between the barrel diameters. So, really, the shapes all wound up all about the same.
The carraiges changed about the same time, an adaptation of carronade-style carraiges. They keyed to a deck pivot of one sort, and had trucks not for recoil control, but for train (horiszontal plane rotation). Recoil was handled using the slide of the upper carriage on the base.
This kind of encompassed several changes. One was much larger guns, so fewer were needed/wanted. Also that such weight was wanted closer to the centerline for stability, and from how the thinking about broadsides had changed in the brief time of sidewheelers.
About the only time you needed to bring a gun (and many were being rifled, too) was to improve train angles, and those were for the "secondary" sized weapons where weight at the rail was not a huge stability issue. Steam allowed something not seen before--manoverability. It mattered less that you only had a 15º arc trhough the rigging for your 100# gun, because you could steer that arc onto your enemy. (While on that attack vector, you could bring your "mere" 32 & 48 pounders to bear from the rails.)
We don't have a ton of documentation of a bunch of this. The pivot muzzle loaders were eclipsed by rifled ML in something like two decades. And breach-loading rifles eclipsed them both perhaps a decade later.
So, did they use a Gun Tackle (3 part) in 1860 and a Double Gun tackle (5 part) in 1880? Lots of argument on that. Dry, academic argument, often plucking phrases out of dusty of tomes & reports. Scant few photographs, sadly.
So, ar the guns lashed to their pviots when stowed? What tackles were used when in Action? The recoil return tackls is usually 5 part along the side of the recoiling slides.
So, the Revell kit is not bad. 5 part tackle at 1/96 is never simple. The aftermarket stuff can be good. Cottage looks better than, say some of the white-metal offerings.
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