Battery Pratt has a disappearing rampart gun, though it’s but a six-incher. There *used* to be larger ones, up to ten inches in that style at Fort Stevens, but they sent those off for scrapping after Ww2. Bummer. (At least there are a pair of “replica Rodman smoothbore” guns in the area. Those were stated as being “ten inchers.” If you want to lay eyes on a “big ten inch,” like the gun spoken of in the G.B. Shaw play “Major Barbara,” you’ll need to go north to Whidbey Island, to a Fort up that way, where they replaced the one they used to have with one from, I think, *Corregidor* in the Philippines. *“… the Undershaft Ten Inch!”*