I wrote earlier this year about visiting Fort Casey, an old army Coast Artillery fort near my childhood home that is now a state park. Pictures from that visit can be seen here. Now, thanks to the magic of YouTube, you can see old training film footage of identical batteries of coast artillery in action.
The batteries at virtually all coast artillery posts were of nearly identical design for each size weapon. That is to say, a 10” disappearing gun at Ft. MacArthur looked just like one at Ft. Casey, or any other fort. If the narrator hadn’t identified where each battery was, I would have sworn the footage was shot at Ft. Casey.