In the early 1900s the US Army maintained a series of large coastal defense artillery. Eventually, these guns grew to be as large as 16" in diameter. AHM makes a US Army railgun that makes a good start for the 16" gun.
I made the gun a few years ago and then stocked the crew with various WWI and early WWII US Army troops. These are a mixture of troops from Airfix, Tumbling Dice, It Figures, and others.
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