Dahlgren in King George County, Virginia — The American South (Mid-Atlantic)
Serial Number 278L
Photographed by Evan Dwyer, October 13, 2023
1. Serial Number 278L Marker
Photographed with permission under the escort of Dahlgren Public Affairs Office personnel.
This 16-inch/50 caliber MKVII battleship gun was manufactured at the U.S. Naval Gun Factory in Washington, D.C. and came to Dahlgren for proofing here on Aug. 22, 1942. It became the centerpiece of Number 2 turret aboard USS New Jersey (BB-62), and was first fired on July 23, 1943. During World War II, it was fired 179 times in the U.S. Navy's South Pacific campaign. In the Korean War, when the USS New Jersey was reactivated, the gun barked out a combat record 824 rounds. On 15 June 1953 this gun, along with its counterparts, destroyed 44 bunkers, closed two caves, demolished 610 yards of trench lines, decimated 13 gun positions, destroyed four mortar positions, and cut six main supply roads. In addition, 20 bunkers, 13 gun positions, and 3 mortar positions were heavily damaged. After the Korean peace accords and Panmunjom, the gun was removed from the battleship, and eventually transferred back to Dahlgren on October 23, 1969 where it fired another 214 rounds in testing
this page online
The gun has a chamber volume of 27,000 cubic inches. It has 96 rifling grooves with a twist of one turn every 25 calibers. Each rifling groove is 0.15 inch deep. The gun can support a maximum service pressure of 18.5 tons-per-square inch with typical muzzle energy of 355 mega joules. It can launch a 2,700 pound armor-piercing projectile more than 12,000 yards, or a 2,240 pound projectile 47,000 yards and can penetrate face-hardened (16-inch thick) armor at (14 nautical miles) 28,000 yards. The weight of the gun is 390,000 pounds. The barrel has not been demilitarized and could easily be placed back in service should the need arise.
Topics. This historical marker is listed in these topic lists: War, Korean • War, World II • Waterways & Vessels. A significant historical date for this entry is July 22, 1943.
Location. 38° 19.585′ N, 77° 2.314′ W. Marker is in Dahlgren, Virginia, in King George County. It can be reached from the intersection of Welsh Road and Jenkins Road. Marker is next to the battleship gun on the Parade Ground at NSWC Dahlgren. Touch for map. Marker is in this post office area: Dahlgren
Photographed by Evan Dwyer, October 13, 2023
2. Serial Number 278L Marker
The marker is visible as the small square by the third upright from left on the test mount for the star of the show, the Mark VII gun from USS New Jersey. The two projectiles in front of the gun mount are one of the types the gun could fire.
Photographed with permission under the escort of Dahlgren Public Affairs Office personnel.
Regionally, this marker is in the American South, specifically in the Upper South, in the Mid-Atlantic, in the Tidewater, in the Chesapeake Bay Region, and on the Eastern Seaboard. Globally, it is in the North Atlantic Region, North America, the Western Hemisphere, the Western World, and the Anglosphere. Historically, it finds itself in what was once the territory of the Mississippian Culture, one of the original Thirteen Colonies, one of the Confederate States of America, and the Antebellum South.
Other nearby markers. At least 8 other markers are within 6 miles of this marker, measured as the crow flies: Parade Field (a few steps from this marker); Historic Guns (approx. half a mile away); Dahlgren's Naval Ordnance Testing (approx. half a mile away); 19 Inch Armor Plate (approx. half a mile away); Civil War Action At Mathias Point (approx. 2½ miles away); Mathias Point (approx. 2½ miles away); Laidler's Ferry (approx. 4½ miles away in Maryland); John Wilkes Booth (approx. 5.1 miles away in Maryland). Touch for a list and map of all markers in Dahlgren.
Another
Photographed by Evan Dwyer, October 1, 2017
3. Battleship New Jersey
Moored at her museum berthing in Camden, New Jersey. The reader may notice that Turret 2 (second from the bow) has all three of its guns - the turrets were designed so that guns could be swapped out as the rifled liner within each barrel wore out. Another gun tube would be inserted in place of the worn out weapon and used until it was also worn out. Each shot fired through a rifle, especially of this size, removed a small amount of material from the rifling within the barrel as a result of the friction, gasses, and explosive energies produced by the shell hurtling through the tube with propellant forcing it forward (this usually included expanding a ring around the base of the projectile that would engage the rifling rings and impart spin on the projectile - for long range accuracy, like a football - while also forming a seal to ensure the pressure of gasses behind the projectile remained contained for maximum velocity). Eventually the rifling would be worn down enough that gasses would leak, velocity would decrease, and spin would be less stable - decreasing accuracy of the shot. Each shot was tracked by personnel within the gun turret, for each barrel, even in practice and training shooting. Once a gun was worn out and removed from the turret, a manufacturing facility - such as the gun factory at Washington Navy Yard - could remove the rifling and replace it, since the rifling was designed as an insertable liner rather than molded into the gun barrel's interior wall.
More about this marker. Marker is within a US Navy installation and restricted to individuals with base access or escorted by a credentialed individual. Photography is not permitted on base without escort and/or approval from the Dahlgren Public Affairs Office.
Regarding Serial Number 278L. The marker chooses a very low range to present for the heaviest projectile (12,000 yards being lower than the average combat range between surface combatants in World War II). See the Navweaps link for a more accurate discussion of ranges by projectile type.
Also see . . . Navweaps Technical Data & History. Compilation of information about the 16"/50 Mark VII naval rifle. Unlike the marker, the range figures given on this page are consistent across shell types. (Submitted on November 1, 2026, by Evan Dwyer of Richmond, Virginia.)
Credits. This page was last revised on November 4, 2026. It was originally submitted on November 1, 2026, by Evan Dwyer of Richmond, Virginia. This page has been viewed 11 times since then. Photos: 1, 2, 3. submitted on November 1, 2026, by Evan Dwyer of Richmond, Virginia.
