Most of us are familiar with the M2 .50 cal. machine gun. It is found on most Coast Guard Cutters. Its familiar. Its simple. It is a stand alone weapon that requires no external power. It is frequently a Coast Guard vessel’s primary weapon, as on the 87 foot patrol boats, buoy tenders, and icebreakers. It is the secondary as on the FRCs and WMECs.

Modern-day air-cooled 0.50″ (12.7 mm) Browning Machine Gun. US Navy Photograph No. 020704-N-0156B-002.

Nominally it has an effective range of 2,200 yards, but I suspect that is only against advancing infantry formations. It is certainly not accurate at that range after the first round in full auto.

Aside from firing warning shots at close range, it is frankly not a very good weapon for use in the naval environment. The gunner is largely exposed, where he can be picked off by a sniper. Even terrorists or criminals can easily obtain weapons that equal or overmatch it range and hitting power. The damage it can do to anything beyond the smallest vessels is very limited.

When used in a crowded harbor, its range, combined with its inaccuracy, and the lack of a self-destruct feature for it projectiles, mean it may cause collateral damage.

It is almost totally useless against aircraft. During World War II, Navy experience was that it required an average of 11,285 rounds for a .50 caliber machine gun to bring down an aircraft. The .50 caliber weapons on ships were credited with 14.5 aircraft kills for 163,630 rounds expended, so it probably not going to be very useful against drones.

We should not expect it to provide an effective self defense capability.

There are things we could do to improve it. We could provide better sights. We could provide protection for the gun crew. We could mount it in a Remote Weapons Station (RWS), but really we could do a lot better.

Northrop Grumman seems to think they have a replacement, perhaps two. Most recent is the 20mm Sky Viper proposed to equip the Army’s planned Future Attack  Reconnaissance Aircraft (FARA) seen in the video above.

As with General Dynamics’ offering, specialty munitions for use against troops, unmanned aerial vehicles, ground vehicles and other helicopters, can be integrated with Sky Viper, flexibility which naturally suggests other applications.

While emphasizing that Sky Viper is a FARA-focused effort (with DEVCOM funding), Canole acknowledges that Northrop Grumman is looking beyond the platform to where it might offer a solution “with a lot more firepower than a .50 caliber”. That could include the Army’s new Mobile Protected Firepower light tank prototypes for which .50 caliber (12.7mm) auxiliary guns are already spec-ed.

“The low recoil and a relatively lightweight system really opens the door for [applications] where .50 calibers tend to be the mainstay,” Canole says.

From Back Left: 40mm grenade casing, 30x173mm (A-10/M44), 30x113mm (M230), 25x137mm (M242/Mk38 gun mount), 20x102mm (Phalanx), 50 BMG; Foreground: 300Blackout (typical rifle round), 9mmx19 (typical pistol round)

The Sky Viper, which uses the same 20x102mm round as the 20mm Vulcan Gatling gun, that equips the Phalanx CIWS, is evolved from the 30mm M230 that fires the 30x113mm. You can see in the photo above that the 20x102mm is a much smaller round than either the 30x113mm or the 25x137mm used by our current 25mm MK38 mounts, but it is substantially more powerful than the .50 caliber.

As the newest member of the chain gun family, we can expect some improvements. Compared to the M230 it has much lower recoil forces, a higher rate of fire, and is lighter, lighter in fact, than the .50 caliber M2.

Apparently earlier the M230 was also seen as a potential replacement for the .50 caliber M2. It still offers some advantages.

It is in service with the Marine Corps, so it is already in the Navy inventory and ammunition supply system. It is actually smaller, more compact, lighter, and has far less recoil than the 25mm M242 in the Mk38 mounts.

Compared to the .50 caliber, the 30x113mm projectile is far more effective against larger targets and is effective at a greater range.

Used in a remote weapon station, it is far more accurate than a .50 caliber M2, and anytime you add a remote weapon station, the ship benefits from the high quality optics that come with it.

Plus there is a programable air burst fuse already available for the 30x113mm round that is apparently effective against drones.

I would not suggest replacing the 25mm Mk38s with either of these, unless the remote weapon station also incorporated missiles like Hellfire/JAGM and/or Stinger, but as replacements for .50 caliber they offer great advantage.