Is There a Replacement for the M2 .50 caliber Machine Gun

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.

 

“BAE Systems Successfully Tests APKWS Laser-Guided Rockets Against UAS” –Seapower

An artist’s conception of an APKWS strike against an unmanned aircraft. BAE SYSTEMS

The Navy League’s on line magazine, Seapower, report the successful test of a new alternative for countering Unmanned Air Systems.

BAE Systems Inc. has successfully tested APKWS laser-guided rockets in precision strike tests against Class 2 unmanned aircraft systems at Yuma Proving Grounds, Arizona, the company said Oct. 11.

The 2.75-inch test rockets combined standard M151 warheads and Mk66 motors with APKWS precision guidance kits and a newly developed proximity fuze, enabling them to engage and destroy airborne drones at a fraction of the cost of traditional counter-UAS strike capabilities.

(A Class 2 UAS is 21 to 55 pounds, operates at 3500 ft or lower, and has a maximum speed of 250 knots, so its pretty small. ScanEagle is an example.)

As important as this cUAS capability may be, adding this capability to Coast Guard Units would also have the bonus of providing both a capability against a range of surface targets from small, fast, highly maneuverable craft to small ships, and at least a basic anti-aircraft capability.

Adding a launcher and the required laser designator to vessels with Mk 38 mod2/3 gun mounts should not be too difficult. The PATFORSWASIA Webber class FRCs would a good place to prototype an installation.

More on APKWS here:

Bahrain Bound FRC gets Upgrades, LRAD and Short Range Air Search

(As we get into this, you may want to click on the photo to get an enlarged view.)

This Spring, the first two Webber class patrol craft are expected to go to Bahrain to start replacing the six 110 foot WPBs of Patrol Force South West Asia (PATFORSWA).  Two more will join them in the Fall and the last two in 2022. Back in 2018, I speculated on what might be done to modify them for duty in this more dangerous area. Apparently the Coast Guard leadership has had a few ideas of their own.

We have some very shape observers among the readers of this blog.

First Andy provided the photo of USCGC Charles Moulthrope (WPC-1141) above and pointed out the Long Range Acoustic Device (LRAD, the gray device mounted near rail on the O-1 deck just this side of the port forward corner of the bridge) and the four round sensors a short way up the mast two on each side. I note these systems were not on the ship when it was handed over by Bollinger (photo below).

The 41st fast response cutter (FRC), Charles Moulthrope, as delivered to the Coast Guard in Key West, Florida, Oct. 22, 2020. It is the first of six planned FRCs to be stationed in Manama, Bahrain. (U.S. Coast Guard photo)

Then Secundius identified the four round sensors on the mast as Sierra Nevada Modi RPS-42 S-Band Radar.

From the Company web site: “RPS-42 is an S-Band tactical hemispheric air surveillance radar system. It is a member of the non-rotating, solid-state, digital radar family Multi-mission Hemisphere Radar (MHR), developed by RADA Electronic Industries Ltd.
“The RPS-42 is a pulse Doppler, software-defined radar platform, that can detect, classify and track all types of aerial vehicles – including fighters, helicopters, UAVs, transport aircraft, etc. at tactical ranges. A single radar platform provides 90º azimuth coverage. Hemispheric coverage is achieved when four radars are employed as a system. Mobile or stationary, the system can be integrated with any C⁴I system and other radars and sensors. The software is able for On-the-Move (OTM) Operation. The radar can operate either as a stand-alone or as part of a large-scale surveillance system.
“The Antenna is an Active Electronically Scanned Array (AESA) based on Galliumnitrid (GaN) Amplifiers. Its diameter is 50.4 cm , the max width is 16.5 cm. (19.8″ x 6.5″ –Chuck)
“The achievable range for detection of the smallest drones (known as Nano UAV) is 3.5 km”

These radars use Galliumnitrid (GaN), the new technology in radar, that allows the AN/SPY-6 to significantly outperform the earlier AN/SPY-1 found on most Aegis equipped warships. (Reportedly a 3000% improvement)

You can get an appreciation of what this is about from this Popular Mechanics article. This Is the ATV-Mounted Jammer That Took Down an Iranian Drone.

There is more here: Light Marine Air Defense Integrated System [LMADIS] (globalsecurity.org)

I’m only guessing, but I would think the FRC would also have the same or equivalent complementary equipment as the LMADIS, e.g. small EO/IR camera, Skyview RF Detection system and Sierra Nevada MODi RF jammer (Photo below, I may be seeing the jammer–pictured below–located above and behind the port side RPS-42 radar arrays, visible between the radar arrays and the tripod legs). The cutters of this class are already normally equipped with electro-optic devices, both on the mast and on the Mk38 gun mount, which can provide a kinetic counter to UAVs.

Sierra Nevada MODi RF jammer. From the company web site, “SNC’s Modi II is the most modern & highly-capable dismounted EMC system in the DOD inventory.”

This was probably what the Commandant was talking about, when he said that Coast Guard PATFORSWA had a counter UAS role in a recent interview.

I am thinking, this radar might also be used on some of our other cutters as well, perhaps the 210s and the six 270s to be FRAMed, to provide them better control of their helicopters on approach in bad weather. The 210s have no air search radar and the 270s will almost certainly lose the Mk92 fire control system which provides their only air search radar currently. Reportedly the radar has a range of up to 30km and an instrumented range of 50km at altitudes from 30ft to 30,000 feet. Apparently the Marines are also using it to direct fire for their short range air defense systems. which includes a 30mm gun and Stinger missiles.

Thanks to Andy and Secundius for kicking this off.