To celebrate the traditional birthday of the world's mightiest fleet, the U.S. Navy, we here at decided to take a look at the maritime service's guns. 

While these days, the Navy's surface forces rely more on their embarked aircraft and missiles of all stripes to do most of the heavy lifting-- especially on targets far over the horizon and stretching to the stratosphere-- make no mistake, there is no shortage of guns afloat. 

5-inch Guns


Today, the largest ordnance, after the retirement of the vaunted WWII-era 16-inch guns of the battleships in the 1990s, is the 5-inch MK 45 guns carried on cruisers and destroyers. The MK 45, currently fielded in 54- and 62-caliber variants with the term "caliber" used here to denote the length of the barrel rather than the bore, can fire as many as 20 47-pound shells out to 14.9 miles and are capable of being used against ships, aircraft, and land targets. 




With the retirement of the last frigates that carried 76mm guns-- although they are still used by the Coast Guard, the MK 110 57mm/70 caliber mount is the go-to medium-caliber gun used on ships such as the Littoral Combat Ship and the planned FF(X) frigate. A Swedish design capable of firing 220-rounds per minute, these compact mounts can reach out to 9 miles. 




The MK 44 30mm gun weapon system, a new platform, is also seeing use, promising to deliver some serious energy to interloping small boats. Here is a test of one against some fast surface drones. 


25mm Chain gun 


The MK 38 25mm/87caliber machine gun system replaced the old 20mm manually-trained MK 16 cannons in the fleet and is ideal against fast attack craft. The stabilized MK 38 was originally a manned gun, like the MK 16, but has since been updated to fire remotely with the aid of an auto-tracking fire control system that includes an electro-optical sensor. Able to fire 180 soda-can-sized shells per minute, the Navy has 500 of these mounts spread across the fleet from patrol boats to aircraft carriers. 


20mm CIWS


Meanwhile, the 20mm MK 15 Phalanx CIWS mount, capable of engaging missiles and low-flying aircraft as well as surface threats, is always a crowd-pleaser with its 4,500 rpm rate of fire. First fielded in 1978, the CIWS has been continuously updated over the years and is on its third (Mod 1B) generation. 




Most vessels also carry .50-caliber M2 heavy machine guns and 7.62 NATO M240 general-purpose machine guns as well. 


Small arms


Navy boot camp still includes basic firearms safety and weapons training with small arms as ships maintain their own defense and boarding teams, where they receive further training. The individual weapons currently in use include the M4/M4A1 carbine and M9 9mm pistol. The latter is being replaced by the M17 Modular Handgun System, a variant of the Sig Sauer P320. Additionally, there are a variety of shotguns and legacy rifles such as the M14 still in circulation for duties such as line throwers and honor guard use. 




Then, of course, there are SEAL and SWCC teams who speak gun in an entirely different dialect than the rest of the fleet. 



And there is also the promise of lasers and rail guns shortly. 


Cover photo: The U.S. Navy guided-missile destroyer USS Gridley (DDG 101) fires its Mark 45 5-inch gun during a live-fire exercise in the Norwegian Sea. (U.S. Navy photo by Master-At-Arms 1st Class Joseph Broyles)

revolver barrel loading graphic