USS Missouri (BB-63) gun on Cape Henlopen
The current naval presence on Cape Henlopen is gun #371 of the battleship, USS Missouri (BB-63).   The Fort Miles Historical Association (FMHA) has brought the parts of the gun to the cape for restoration, assembly and display as part of a military museum, which is being planned in conjunction with the Delaware State Division of Parks and Recreation and Cape Henlopen State Park.  
The initiative for the effort originated with Dr. Gary Wray, President of the FMHA and the Coast Defense Study Group.  The initial fund-raising campaign to bring the barrel to Cape Henlopen was led by Mr. Nick Carter, scion of a Navy family and 1970 graduate of the U.S. Naval Academy. He was supported members of FMHA including Captain William Manthorpe, USN (Ret. and USNA 1955).
Local governments, Delaware Foundations, the General Motors Foundation, Fort Miles Historical Assn., local businesses and residents as well as members of USNA classes of 1955 and 1970 were generous in their support. 

Nick Carter and gun barrel, 7 May 2012 
The barrel was moved from St. Julian's Annex of the Norfolk Naval Base to Cape Henlopen by barge, rail and truck.  It was stopped for a welcoming ceremony and public viewing at Georgetown, Delaware.

Additional parts were later trucked from the  Naval Surface Weapons Center at Dahlgren, VA to Cape Henlopen.  (see those parts below.)
This gun was produced by the U.S. Naval Gun Factory, Washington DC. It is a 16"/50 caliber gun, meaning that the barrel has a bore of 16" in diameter and a bore length of 800 inches which is 50 times the diameter. 

Designation: 16 inch/50 caliber, Mark 7
Gun Weight: 267,904 lbs or 134 tons (including breech).
                     239,156 lbs or 119.6 tons (without breech).
Gun Length: 816 inches or 68 feet (breech to muzzle).
Bore Length: 800 inches.
Rifling Length: 682.86 inches.
Grooves: 96, 0.150 deep.
Chamber Volume: 27,000 cubic inches.
Rate of fire: Two rounds per minute.
Range: 23.5 miles.

Nine such guns were installed in three turrets, two forward and one aft, on the Missouri.  This gun, serial #371, was the center gun in turret one, the lower forward turret.
During WW II, Missouri served in the Pacific theater from January 1945. first as the flagship of Vice Admiral Marc Mitscher's Task force 58 during the Iwo Jima campaign where her 16 inch guns provided direct and continuous support of the invasion landings.  Subsequently, she supported carrier operations against the Japanese Home Islands and provided preliminary bombardment of Okinawa.

In April, Missouri became the flagship for Admiral "Bull" Halsey's Third Fleet, returning to Okinawa for two months of operations. In July, she led Third Fleet operations into the heart of Japanese inland waters, shelling the Home Islands.

     USS Missouri firing center guns of forward turrets.
Missouri served as the venue for the signing of the formal surrender documents ending WW II on 2 September 1945. 

The surrender signatories and parties formed up on the starboard side of the ship, forward, alongside turret 1 and gun #371.

Lieutenant Commander William J. Kitchell of Delaware led the American party to the signing table. The table was positioned on the starboard side, alongside turret 2.
Fleet Admiral Chester W. Nimitz USN signed the surrender document as the U.S. representative.  

Standing behind him are General of the Army Douglas MacArthur, Admiral William F. Halsey USN and Admiral Forest Sherman
From September 1950 until March 1951 Missouri performed screening operations for carriers and shore bombardment in Korean waters. From June to August 1952 she conducted a Midshipman's cruise carrying Third Classmen from the class of 1955, among others.  

From November 1953 until April 1954 the ship was overhauled and gun serial # 371 and others were removed and replaced.
Gun parts now at Cape Henlopen for restoration
Breech and barrel 
 Muzzle and 16 inch shell. 

The guns were designed to fire two different 16 inch shells: a 2700 pound  armor piercing (capped) round for anti-ship and anti-structure destruction and a high explosive 1900 pound round used in shore bombardment.
 
The 17 inch thick piece of armor plate shows a hole made by a 16 inch armor piercing round.
 
Barrel Slide
Gun Base
Restoration has begun on the gun parts
High pressure sand blasting of the gun base is much easier than paint chipping.
Painting of the barrel slide is already completed. 
By Memorial Day 2016, after much work by volunteers of the Fort Miles Historical Society, the gun had been reassembled and moved to its final location.

The gun is elevated at 12-13 degrees and pointed at the Fort Miles tower located 14 miles across the bay at Cape May. 

At that point the concrete pad remained to be poured, lighting was being installed and plans were underway to create the plaza surrounding the gun, including installation of the bricks purchased by those who help pay for the movement of the gun and the work that has been accomplished.
On September 2nd Delaware Governor Jack Markel cut the ribbon marking the official opening of the Fort Miles Artillery Park while assemble state and local legislators, Delaware State Park Officials, Fort Miles Historical Association members and visitors looked on.

The center piece of the Artillery Park is the restored and remounted gun barrel #371 from the USS Missouri (BB-63). 
Work is progressing on the movement of other guns and landscaping to create the gun park. The infrastructure work on the museum has been virtually completed. New exhibits are being created and tours are conducted on a twice weekly basis and on special occasions. 

Photo Credits:

-Missouri gun at Naval Surface Warfare Center, Dahlgren, VA.: Photo by Mr. George Watts of Fort Miles Historical Assn. published in Cape Gazette, 7 Feb. 2014.

-Mr. Nick Carter and Missouri gun at Cape Henlopen. Author photo.

-Missouri gun passing Georgetown, DE. Author photo.

-Missouri guns firing. U.S. Navy photo, Naval Heritage and History Command.

-Lieutenant Commander Kitchell leading party to surrender table. U.S. Navy photo, published in News Journal Wilmington DE., 12 June 2014.

-Admiral Halsey at surrender table. U.S. Navy photo.  Naval History and Heritage Command.

-Missouri gun parts at Cape Henlopen for restoration. Author photos.

-Missouri gun parts under restoration. Thanks to Joe Stormer

-Gun in placre. Author photo..

-Gun dedication courtesy of Delaware State Parks and Fort Miles Historical Assn.

-Gun. Delaware Cape Gazette.

-Gun park plans. Delaware State Parks.