Here's What It Takes To Fire The Biggest Gun On The USS Barry

USS Barry 5-Inch GunRobert Johnson — Business InsiderThe USS Barry’s 5-inch gun during a live fire exercise off the US Atlantic Coast

When I hauled myself aboard the Arleigh Burke-class guided missile destroyer USS Barry, one of the first things I was shown was the ship’s 5-inch, 127mm gun.

“This is how the Barry pays its bills,” the ensign showing me around said.

What she meant was that even though the Barry carries an array of missiles including Tomahawks, SM-2s, and SM-3s, among others, the 5-inch is the weapon of choice when engaging any surface, air, or shore targets.

Loaded with an assortment of devastating rounds the gun can pound out its 20-projectile magazine in about a minute while maintaining pinpoint accuracy through computerized targeting.

The crew of the USS Barry allowed me to poke around into all aspects of the 5-inch weapon, allowing me to explore deep in the ship’s magazine, as well as the firing room.

What goes into making this gun so devastating may surprise you.

This post was originally reported, written, and produced by Robert Johnson

The 5-Inch Light Weight Gun Mount is the Navy's main anti-surface gun.

The 5-inch is more economical than a guided missile and extremely accurate up to about 15 miles away.

In a time of conflict the order to fire the gun comes from here: the bridge of the USS Barry. But getting the weapon to fire and making sure it hits the target requires coordination among people all over the ship.

The deck has to be covered in protective mats to keep the hot discharged shell casing from damaging the deck's non-skid surface.

Once the bridge receives information on a target it relays that information to the room behind this door. In this room, the ship's sophisticated sonar and radar systems track, isolate, and target all threats in the area.

Once the target is isolated and the trajectory locked the order to fire comes down here to the gunners' room below the 5-inch.

Gunners are allowed to skip shaving the day of a test-firing -- based on a perhaps superstitious belief that shaving can cause the gun to malfunction. After a small issue during the test, the enlisted gunners blamed their Chief here, who had shaved that morning.

With so many working parts that must come together, the gunners have a special relationship with their weapon. They have named this 5-inch Lucille.

The projectiles weigh 70 pounds apiece and are delivered up here from far below in the 'Deep Magazine.' They are then loaded into the slots behind that wire mesh.

The firing mechanisms are accessible here -- and with the gun firing now, a ratcheted metal arm swings back and forth like mad, firing and ejecting the casings of five projectiles.

Up off the bridge, the Barry's XO and Captain (on the left and right, respectively) look into the distance at the results of the test.

This is what they're looking at as the rounds detonate on a time-delay fuse.

These previous steps are the result of many more that begin down here in the Deep Magazine.

This is where the various shells for the 5-inch and the powder charges are stored.

In one room are the rounds, still in canisters, that get delivered from the dock via an elevator at the far end of the room.

Another room stores the powder that shoots the projectile from the gun.

When the gun needs to be fired a team will come down here and open this lift.

They then unpack the powder charge from its canister ...

... and put the powder here at the bottom of the lift where it locks into place.

They then put a projectile much like this one on top of the powder.

Each projectile carries a specific type of tip.

The lift delivers the load back up to the firing room ...

... and again -- the rounds get placed into the rack beneath the base of the gun where they will sit until the order to fire arrives.

When that happens the blast is deafening. And thanks to a highly accurate targeting system, it's terribly deadly as well.

The Navy's 5-inch is great for the sea, air, and shoreline...

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