This Is What It Takes To Fire The Biggest Gun On The Destroyer USS Barry

The USS Barry’s 5-inch gun during a live fire exercise off the US Atlantic Coast

Photo: Robert Johnson — Business Insider

When I hauled myself aboard the Arleigh Burke class guided missile destroyer the other day, 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 via its computerized targeting.

The crew of the USS Barry allowed me to poke around into all aspects of what makes the 5-inch weapon tick, from deep in the ship’s magazine, to the firing room, to on deck when the weapon was fired.

All that happens to make this gun so devastating may surprise you.

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 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 cooperation from people all over the ship

When time allows — the deck gets covered in protective mats to keep the hot discharged shell casing from damaging the non-skid surface of the deck

Once the bridge receives information on a target it relays to the room behind this door where the ships sophisticated sonar and radar systems track, isolate, and target all threats in the region

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 belief that to shave 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've named this 5-inch Lucille

The projectiles weigh 70 pounds apiece and are delivered up here from far below in the 'Deep Magazine' and 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 on the left and its Captain on the right — look into the distance at the results of the test

And this is what they're looking at as the rounds detonate out here on a time delay fuse

But even 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 via elevator at the far end of the room from the dock

In another room is stored 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

Unpack the powder charge from its canister

Place the powder here at the bottom of the lift where it locks into place

And put a projectile, much like this one used for training, on top of the powder

Each carrying 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'll sit until the order to fire arrives

And when that happens the blast is deafening and thanks to a highly accurate targeting system — terribly deadly as well

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

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