Tag Archives: resurrected weapons

Resurrected Weapons: Project Babylon

Back in the 1950s, when rocketry was extraordinarily difficult, and TV was full of videos of NASA rocket tests failing miserably, Gerald Bull had an alternative idea: Use a giant gun to put a payload in orbit. This led to Project HARP, which got a lot of great research done. By the 1960s, we had figured out (mostly) how to make rockets that work. It was still hard, but now we could generally expect launches to work. And so the plug was pulled on HARP, but Gerald Bull still dreamed of using a giant gun to put a satellite in orbit. Eventually, in the 1980s, he found someone with money willing to back his dream once more. That man was Saddam Hussein.

Project Babylon came in two phases. Stage one was “Baby Babylon”, a proof of concept model with a 350mm bore and a barrel length of 46 meters. This was initially used for horizontal testing, and was then erected on the side of a mountain. The full size “Big Babylon” would have been the biggest gun ever, with a one-meter bore and a barrel length of 156 meters. The original design was intended to be suspended from a steel framework by a system of cables.

Testing of the Baby Babylon cannon showed issues in dealing with seals between the barrel sections. While these were being fixed, Gerald Bull was assassinated outside of his Belgian apartment on March 22, 1990, which crippled the project. It would not be resumed after the First Gulf War.

Bull’s assassination was almost certainly not due to his work on Project Babylon. The superguns were massive, fixed targets. Easy to spot with aerial or satellite reconnaissance, easy to destroy. But Bull was also working on improving the range of Saddam’s Scud missiles. Those are much more effective than a giant gun. This was the project that most likely angered Saddam’s enemies enough to get an assassination. The most likely candidates are Israel or Iran, both of whom have intelligence agencies with lots of experience in liquidating potential problems.

Project Babylon itself is also extremely problematic. It’s a lousy weapon, as we’ve mentioned before. But I’m also extremely skeptical of their utility as a launch system. Even with a 156 meter barrel, the acceleration is going to be absolutely brutal. This is going to seriously restrict the payloads you can launch. A rocket is going to be far gentler on the payload, and much less likely to wreck a satellite. Plus, rockets can accept oversize shrouds to handle larger payloads, or be clustered to lift more weight. You’re pretty stuck with the weight capacity and payload diameter restriction here.

Verdict: Funding Request Denied by the Borgundy Ordnance Board

Resurrected Weapons: AGM-129A/B ACM

The AGM-86 Air Launched Cruise Missile was a great way to extend the service life of the B-52. Now, despite the massive Soviet air defense network, SAC’s beloved manned bombers could rain nuclear hellfire down on godless communist scum from over 1,500 nautical miles away. Perfect for keeping big, slow bombers away from fancy air defense systems. And we’ve seen the effectiveness of cruise missiles with conventional warheads many times in Iraq.

But those commies had innovations of their own. They managed to make look-down/shoot-down radars for their advanced fighters, and even had a native AWACS by the 1980s. These could spot the small AGM-86s and shoot them down. One of the key goals of SA-15 was to be able to successfully engage inbound AGM-86s.

You probably guessed the answer to the above problem: stealth. Enter the AGM-129. The Advanced Cruise Missile.1 It had modern, low observability shaping and radar-absorbent material coatings to make it as sneaky as possible. Now it could exploit imperfections in radar deployments, with a vastly reduced detection range allowing it to elude Soviet air defenses. The AGM-129 also had an improved version of the Williams F107 engine that powered the AGM-86. The newer F112 used advanced internal coatings to reduce the thermal signature of the AGM-129. It also brought large improvements in range over the AGM-86’s 1,500 nautical mile reach, though the exact range figure for the ACM remains classified.

The guidance and navigation systems were also improved, but again, remain classified. Russian sources2 give it a CEP3 of 16 meters.

The AGM-129 used the same 5-150 kiloton warhead as used on the AGM-86, the W-80. It was also only marginally longer than the AGM-86, so it could still fit in the bomb bay of a B-52. However, it was about five inches fatter, had a wingspan two feet shorter, and was more than 550 lbs. heavier. And, of course, the stealth coating requires more maintenance. Here was the ultimate standoff weapon for the venerable BUFF, just in time for the end of the Soviet Union. Production numbers were repeatedly slashed, from 2,500, to 1,460, to 1,000, and then to the final total of 460 missiles.

Higher maintenance costs would eventually doom the AGM-129 to withdrawal from service in 2012. Which is a shame, because even if you’re not big into nuclear strikes, a conventional variant4 would be very useful against nations with modern, integrated air defense systems.

Verdict: Funding Approved by the Borgundy Air Ordnance Procurement Board

 


  1. A very creative name. 
  2. Seriously, they are the only ones that are willing to hazard a guess. 
  3. Circular Error Probable, i.e. the size of a target that the guidance/navigation system has a 50% chance of hitting. 
  4. To the best I am able to determine, no such variant was proposed. From other conventional variants of cruise missiles, we can reckon that replacing the W-80 with high explosives would give an approximately 1,000 lb warhead. 

Resurrected Weapons: FIM-92 RMP Block II Advanced Stinger

The Stinger missile is a hugely successful MANPADS, but it does have cancelled variants, and that’s what we’re going to talk about today. First, a brief discussion of the Stinger.

The FIM-92 Stinger is a man-portable SAM, designed in the late 70s to replace the earlier FIM-43 Redeye. The Stinger is 5 ft. long, 70mm in diameter, and weighs about 34 lbs in its launch tube ready to fire. Unlike Mistral or Starstreak, Stinger is fired from the shoulder, not a tripod.

Stinger has an effective firing range of about 5 miles, due to the nature of its seeker. It uses a dual-spectrum IR and UV seeker. Adding the UV spectrum makes the job of countermeasures designers harder. The countermeasure now has to duplicate the signature of the aircraft across two spectra, not merely the infrared one.

Stinger has been deployed in several conflicts, and has proven effective. It’s easy to use and good at denying aircraft the use of lower altitudes, forcing them out of its engagement envelope.

In addition to use in the man-portable role, the Stinger is deployed on the M1097 Avenger SHORAD system, the Bradley Linebacker, the Stryker-MSL, and as an air-to-air defensive missile aboard Apache helicopters.

And now we come to the RMP Block II program. This integrated the focal plane array IR seeker from the AIM-9X missile onto the Stinger, which brought two key improvements. To understand these, let’s look at what exactly a focal plane array is.

A focal plane array is an array of light (in this case, infrared-spectrum) sensing receptors placed at the focal plane of a lens. It’s also known as a staring sensor, because that’s exactly what it does: it stares. Unlike a more conventional scanning array, it doesn’t build an image from narrow slices rastered across the field of view. Instead, it looks at the entire field of view all the time.

As I said, this brings two major improvements. First, the focal plane array seeker is a lot better at detecting targets than the old dual-wavelength scanning-type seeker, which gave the RMP Block II a larger engagement envelope and longer effective range. The second is a significantly better seeking capability, which translates into both improved performance in cluttered environments and significantly higher resistance to countermeasures. The imaging capabilities of a focal plane array seeker make them extremely difficult to deceive. The RMP Block II would have had good performance against advanced aircraft flying low and firing off decoys, cruise missiles, and UAVs.

The RMP Block II program was cancelled in 2002 for cost reasons. The war on terror was ramping up, and the money was needed elsewhere.

I can understand cost concerns for a MANPADS system if there are other vehicle-borne SHORAD systems available. For the US, there have been a wide variety of recent developments in SHORAD, helpfully linked above. Unlike previous attempts, these are deploying off-the-shelf missiles for the SHORAD role, including the AIM-9X, which has a motor that’s a better ballistic match for the range capabilities of the FPA seeker. The Stinger is already reasonably effective at denying lower altitudes and getting aircraft to fly higher, and low cost encourages wide deployment. I’m inclined to use the money for other things.

Verdict: Funding Denied by the Borgundy War Department Army Ordnance Procurement Board

Resurrected Weapons: XM307

Here’s yet another attempt to replace the Mk. 19 GPMG and/or the venerable M2 HMG. The XM307 was part of the same program that gave us the XM29 OICW, and later the XM25 once the OICW failed. The program itself emerged from a 1980s study saying that weapons development had reached a plateau, and that the next breakthrough would come with the integration of airburst-fused high explosives into the US Army’s weapons. They had tried to schedule a breakthrough in the late 1960s with SPIW. They failed. Now, a new generation of engineers would try their hand.

The XM307, or Advanced Crew Served Weapon (ACSW), had the same airburst principles as the XM25 and XM29. The gunner would use an integrated fire control system to get the range to target with a laser rangefinder, set an airburst distance, and then shoot rounds at the target. Except now with automatic fire. Let’s look at a quick size comparison chart:

XM307M2Mk. 19
length52.2″65.1″43.1″
barrel length25.1″45.0″16.25″
weight50 lbs.83.78 lbs.77.6 lbs.

It’s definitely lighter. Plus, it’ll bring a flatter trajectory than the 40mm grenades of the Mk. 19, so it should be easier to score hits with. Those are pluses. And, the M2 doesn’t pack an explosive punch. All good things so far for the XM307. So let’s talk lethality.

From autocannons, we know that autocannon ammunition makers don’t think a 25mm autocannon shell holds enough explosives to make an airburst fuse option worthwhile. We know there are lots of deployed 25mm systems, so there’s plenty of incentive to try. Big market, but nobody’s bothered. This isn’t a perfect comparison, of course. Sizes may vary, but if there’s a difference, the autocannon has the bigger projectile. A 40mm Bofors fires a much bigger round than the 40mm Mk. 19. Still, it’s cause for concern.

More concern comes from the test deployment of the XM25. In Afghanistan, while there are plenty of accounts of airburst rounds scaring Taliban fighters away, there are no accounts of it actually killing anyone. And this should be its best chance for success: taliban fighters don’t wear any kind of protective gear. None. If it can’t get kills there, what about when it encounters troops wearing actual modern armor? At least the Mk. 19 has a long history of being effective against unarmored opponents. It starts somewhere. Also note that lots of comparisons with 40mm grenades make a comparison between 25mm Airburst HE-Frag and 40mm HEDP, which is going to be less effective in the pure-antipersonnel role than 40mm HE/HE-Frag.

Now, the XM307 has automatic fire capability, and a belt feed, unlike the XM25. We’re not limited to a one round for one round comparison, which means we’re going to get into “stowed kills” type computations. Clearly, the XM307 holds more grenades in a box than the Mk. 19, so we can try to come up with some notion of relative effectiveness. Or we could, if we had a lot of ammo and a proving ground. Unfortunately I don’t, and I don’t know if the US Army tried this computation. The XM307 was cancelled in 2007.

Another obvious option is to integrate the airburst fusing and targeting system into existing 40x53mm grenade systems. So you’d still have the option of using existing grenades that work, plus you wouldn’t have to develop an entirely new round and ammo system. Someone at DoD actually thought of this, and the Mk. 47 was born. It’s lighter than the Mk. 19, fires the same 40x53mm grenades, and is equipped with a targeting system to set the fuses of airburst grenades. In US Service, that would be the Mk. 285. It’s in limited use in the US Military, and has seen export success with Israel and Australia. So let’s go with that, because it’s way less cost and risk.

Verdict: Funding Denied by the Borgundy War Department Ordnance Procurement Board

Resurrected Weapons: The LWMMG

Around 2010, General Dynamics independently1 developed what they called the Lightweight Medium Machine Gun. This weapon was designed to fill the “capability gap” between the M240/MAG-58 GPMG, chambered for 7.62x51mm and the M2 Heavy machine gun, chambered for 12.7x99mm. The idea was to be able to “overmatch” enemy PKMs in a weapon that was still man-portable like an M240.

The cartridge chosen was the .338 Norma Magnum2. This cartridge was designed to fire the excellent 300 grain HPBT .338 projectiles from rifles that had actions too short to accept the .338 Lapua Magnum cartridge. It was chosen for this application for its excellent ballistic performance at range, to really allow the LWMMG to stretch it’s legs.

Clearly, the .338 Norma Magnum has a lot more recoil energy than the 7.62x51mm round used in the M240. But General Dynamics wanted to maintain portability, and their goal was to maintain the “footprint” of the M240. So it couldn’t be too much heavier or larger. To accomplish this, General Dynamics used the same recoil system they had developed for the XM806. Having the barrel, gas system, and bolt recoil together meant they could distribute recoil forces easier, and not have to use as much weapon mass to do so. The LWMMG ended up being able to use the same tripods as the M240, and is three pounds lighter than the US Army standard M240B. Later versions of the LWMMG cut two more pounds off the weight.

The US Military opted not to procure the weapon, and I don’t really blame them. While the weapon is about the same weight as the current GPMG, the ammo is heavier, round-for-round. And, frankly, the extra range over 7.62×51 is usually wasted, because of line of sight considerations or target discrimination considerations. If you are in PKM range, he is in M240 range. Or range of vehicle weapons. Or mortar range. There are lots of other ways to deal with that sort of opponent. And you’d be adding another round type and spares type to the logistics trail. The use of other weapon systems is an even better idea if the enemy comes with modern body armor.

Let’s get some numbers on the ammo weight side, since this ends up being pretty significant. We’ll look at the weight of 100 linked rounds of 7.62×51, .338 Norma Magnum, and .50 BMG. 100 rounds isn’t a basic load, but it’s a nice round number to work with. Your basic load/vehicle load will probably be some multiple of that.

  • 7.62x51mm NATO — 6.625 lbs.
  • .338 Norma Magnum — 12 lbs.
  • 12.7x99mm BMG — 29 lbs.

Can it replace other weapons? I wouldn’t use it to replace existing 7.62x51mm GPMGs, because of ammo considerations and because that range is really not needed in general. It’s wasted on the regular infantry and the training and optics available to them, plus it’s almost twice as heavy. The .338 Norma Magnum round is also entirely too powerful for a semiautomatic or select-fire Marksman’s rifle, so 7.62x51mm would stay in the inventory. The LWMMG also isn’t going to replace the M2, because you’re giving up some range and a lot of soft target terminal performance with the smaller, lighter round. To be fair, General Dynamics never proposed it as such. It’s a marvelous technical solution in search of a problem. Cool, but I’d rather spend the money on other things.

Verdict: Funding Denied by the Borgundy War Department Army Ordnance Board


  1. I.e. without a solicitation or RFP from the DoD 
  2. Not to be confused with .338 Lapua Magnum, which is a bit longer. 

Resurrected Weapons: XM806 Heavy Machine Gun

The Browning M2 is nearly 100 years old, and it is still a very effective weapon. It is heavy and made with decidedly old-school manufacturing techniques. The XM806 was an effort to replace it with a newer, lighter machine gun, still chambered for the classic 12.7×99 mm BMG round. The XM806 was a development of the cancelled XM312, which was a prospective heavy machine gun that could be easily converted to fire 25×59 mm airburst grenades.

The XM806 preserved the recoil system of the XM312 (and its grenade launching sibling, the XM307). This system had the barrel and bolt move forward when the trigger is depressed, forcing recoil forces to overcome the forward momentum of both the bolt and barrel.

The XM806 weighs only 40 lbs (18 kg), less than half the weight of the M2. It has less recoil than the M2, and it’s also easier to disassemble. On the other side, it has about half the rate of fire of the M2. For present uses, a reduced rate of fire probably isn’t a huge deal. We’re long past the days of expecting a heavy machine gun to be an effective antiaircraft gun.

While the weight savings are eye-popping, one might question the point. 40 lbs is still too heavy to easily manpack, and the weapon is still very bulky. And 12.7mm BMG ammo is big and heavy. It’s going to be a bother for a team of light infantry to deploy, and they’re probably going to be better off with GPMGs supplemented by antitank weapons, not least because of the weight of the ammo. As for vehicles, the difference between 40 and 84 lbs is basically immaterial. We can mount M2s on dune buggies. We can mount M2s on aircraft and helicopters. The weight savings really don’t get us much in terms of more usability in the roles that we normally find ourselves using a heavy machine gun. And (again) we still have the weight and bulk of ammo to deal with either way, which is a much more significant issue for small vehicles.

Probably a depressing way to look at it. But the biggest thing here would be cost, and it’s really hard to compete with an established system. When the US Army cancelled the project, they diverted funds into improving the venerable M2, and I can’t fault them for it. At least the XM312 added a new capability.

Verdict: Funding Denied by the Borgundy Army Ordnance Development Board.

Resurrected Weapons: LOSAT/KEM/CKEM

I’m lumping these together because they all operate on the same basic principle, and are really just different sized versions of the same concept. This idea keeps coming up in a bunch of different sizes and a bunch of different guises.

Antitank missiles today use shaped charge(s) to penetrate armor. We might call this a “chemical energy” method of penetrating armor. More technically, we might call it the Munroe Effect. This is really effective, and doesn’t depend on missile speed. However, there are lots of technologies today to counter this method of armor penetration, including reactive armor (both explosive and non-explosive types), spaced armor, various forms of composite armor, and cage armor. And we can mix and match the above to get some really hard to kill vehicles.

That said, the clever observer will note that most tank guns today use some kind of APFSDS round, a kinetic energy penetrator. Heavy alloy dart moving very fast. Present armor technology makes this a lot harder to defeat than a shaped charge. LOSAT (later renamed KEM) and CKEM would try to apply this same warhead type to an antitank missile. Start with a heavy metal warhead, add a big honking solid fuel rocket motor and fulfill your need for speed.

The missiles were a little different. MGM-166 LOSAT/KEM was 2.85 m long, 16.2 cm wide, and weighed 80 kg. It had a top speed of about 1,500 m/s or 5,000 fps. At this speed, it reached its maximum range in under 5 seconds.

CKEM is the newer, Compact version of the concept. It’s also faster because of rocket motor improvements. It was build in the late 90s/early 2000s to fit a roughly TOW-sized footprint. CKEM was a little longer than TOW at 1.5 m, but matched it’s 15.2 cm diameter. Maximum speed was Mach 6 (about 6,700 fps or 2,047 m/s).

This ends up being a great idea for a number of reasons. We’ve already mentioned that it’s a lot harder to protect a vehicle against APFSDS type rounds. In this case, there is no replacement for velocity. You’ll need heavy armor to stop what’s incoming. Further, a lot of the complicated guidance systems can be done away with. Both missiles had minimal guidance, and relied on lead computations in the launcher to account for any target movement. Given the speeds involved, this is more than sufficient. Finally, being a very fast moving, relatively unfragile thing, it’s a lot harder for modern active protection systems to defeat. All big wins.

Downsides? Well, most of the development and system cost is the motor. We need a relatively small engine that can deliver a lot of thrust very quickly and will also remain stable in storage. That’s not really insurmountable, or a terrible cost driver. Especially when compared to the high-end thermal-imaging based fire and forget systems around these days. The other obvious problem, which doesn’t come up in documentation I’ve seen, is minimum ranges. Even a really high impulse motor will take some time to accelerate that missile up to speed, so there’s going to be a dead zone where the missile will not work as advertised. I’d also expect the motor to be bulky.

Bulk, even for the smaller CKEM, is still an issue. It’s certainly not man-portable. But it would make an excellent antitank missile for vehicles. A JLTV, or a Bradley would make a great carrier vehicle for these. We love tanks, and thus we love antitank missiles. Just like the Russians, who have new tanks. As do the Chinese.

Also, I’d love to see these trialed from helicopters and aircraft. The size isn’t terrible, and the speed should help with the fire control problem.

Verdict: Funding approved by the Borgundy War Department Army Ordnance Board

Resurrected Weapons: FN BRG-15

In the late 1980s, FN tried to develop a replacement for the venerable Browning M2. They also tried to develop this weapon to match the power effects of the Soviet KPV machine gun, which is chambered for 14.5×114 mm. This round is a tremendously powerful heavy machine gun round, able to penetrate 10 mm of steel armor, angled at 30 degrees at a distance of 1,350 m.

This took quite a bit of effort. Originally FN tried necking the Hispano-Suiza 20 mm round down to 15 mm, but this tore up the barrels too quickly. They eventually settled on 15.5×115 mm rounds with a driving band, much like a very small artillery shell. Also interestingly, they used a necked-out KPV case as the base for their new cartridge. This protracted development cycle did nothing to help the cost of FN’s new weapon.

The BRG-15 itself possesses some curious design elements. It is a dual-feed weapon, feeding from both sides simultaneously. Spent cases are ejected out the bottom. The BRG-15 also possessed a quick-change barrel system. It was 2.15 m (just over seven feet) long overall, and weighed 60 kg (just over 132 lbs) without a tripod, of course. Contrast this with an overall length of 1.65 m (5.4 ft) and a weight without tripod of 38 kg (83.78 lbs) for the Browning M2.

The BRG-15 was cancelled in the early 90s when a lack of buyers and troublesome finances at FN forced them to be selective about their projects. They chose to focus on development of the P90 instead.

This is a case where I actually agree with the termination decision. Clearly, the KPV provides similar, though somewhat inferior, ballistic performance. The KPV was also designed in 1947, so it’s going to be much cheaper to acquire either directly from the Russians or on the secondary market.

Further, in the current age, I do not see the value of such a weapon. The Browning M2 is not a perfect weapon, but it and its ammo are firmly established in our arsenal. The BRG-15 adds considerable weight and bulk in both weapon and ammunition for vehicle mounts or manpack loads. While it is able to perforate most classic APCs, more modern vehicles have the edge in protection. 15.5 mm is also too small to provide a useful explosive payload. The larger 20 mm is a marginal, obsolescent autocannon caliber for vehicles, both in terms of armor penetration and explosive payload. 25 mm is increasingly being seen in a similar light.

At present, the heavy machine gun is a secondary weapon. A weapon to supplement the primary armament of vehicles, or to provide armament to otherwise unarmed light vehicles. Here the lighter, lower cost weapon holds the advantage, even if it is less effective overall at penetrating armor. There are few enough targets that the BRG-15 can defeat but the Browning M2 cannot that it is not worth deploying the heavier BRG-15.

Here, I find myself in agreement with the Russians once again. Having developed the KPV in the late forties, and hence having a cheap, established weapon in the same size and performance class as the BRG-15, they have chosen instead to focus and primarily field weapons that fire the 12.7×108 mm round. In other words, they have opted for weapons in the same performance class as the Browning M2 when cost is much less of an issue.

Verdict: Funding Request Denied by the Borgundy War Department Army Ordnance Board

Resurrected Weapons: M4A1 PIP

The M4 is by no means a terminated weapon. But it could do with some improvements to bring it in line with advancements in the civilian AR-15 sector, and to take advantage of hard won battle experience.

Recall that the standard M4 is an AR-15 configured as follows (there are other features, but these are the salient points):

  1. Barrel Length: 14.5″
  2. Barrel Profile: A2 type (or “Government” type)1
  3. Revised feedramps on the upper receiver (“M4 feedramps”)
  4. A 7″ (“carbine length”) gas system
  5. Round plastic handguards with dual aluminum heatshields
  6. A flat top upper with the MIL-STD-1913 (“Picatinny” rail) on top
  7. A trigger group with capability for semiautomatic and three round burst fire
  8. A four-position collapsible stock (and the necessary receiver extension and buffer system changes for this to work)

Great. Of course, time marched on. And as we became engaged in the War on Terror and deployed troops, soldiers found that they had a bunch of other stuff that they wanted to mount to their rifles. Lights, lasers, that sort of thing. So the plastic handguards were replaced with the Knights Armament Rail Interface System.2 This system is a drop-in replacement for the earlier handguards. It does not require any special tools or disassembly of the upper to install. It is not free-floated however. It is also not very rigid, since it uses the same delta ring attachment method as the stock handguards. Good enough for an IR laser for use at night, but hardly for mounting more precise sights.

I should also point out that Colt rolled a bunch of improvements into some of the small parts of the M4. I will not discuss them much here, but note that they exist. One of them was moving from a “carbine weight” buffer to the “H1” buffer, which is heavier and made the M4 run more reliably.

After a number of battles, the US Army wanted to make some changes to their M4s. The result is called the M4A1. The following major changes were made:

  1. Barrel profile revised to “SOCOM” profile. This is a medium-weight profile, adding mass under the handguards. It adds about 0.25 lbs of weight to the carbine.
  2. A revised trigger group capable of semiautomatic and fully automatic fire.
  3. A heavier buffer for better reliability

The revised, heavier profile was to make the rifle perform better when providing sustained fire. It will also mean that a shooter’s groups will not open up as much after shooting a bunch. Replacing the three round burst with fully automatic results in an improved trigger pull, even in semiautomatic mode, a more useful capability, and more predictable results. The burst cam was an awful idea, and it’s good that it’s gone.

The M4A1 PIP (also known as the M4A1+) was designed to add some more capability to the M4A1. The rifle would be as an M4A1, but with the following additional changes:

  1. A new, more effective flash hider
  2. A longer, free float handguard (likely the Daniel Defense M4 RIS II3)
  3. ‘coyote tan’ coloring on the handguard to break up the outline of the rifle.
  4. A low-profile gas block
  5. A folding front sight
  6. An improved (read: larger) charging handle
  7. An improved trigger

The M4A1 PIP program was cancelled in June 2016 when the Army decided the upgrades were not worth the effort.

Sigh.

That is absolute nonsense. Observe the USMC moving towards getting M27s in the hands of everyone. Most of those improvements are actual, serious improvements on the M4A1 design. While #6 and #7 in the PIP changelist above might not be cost effective, the rest are very good.

A longer, free float handguard is the biggest and most obvious benefit. I finally tried a long (13″) handguard on Bridget, my competition rifle. And I really, really like it. It’s not about looking cool.4 The longer handguard gives you more options for where to put your hand, gives you more room for mounting accessories while still having a place for your hand, and is better to rest on a barricade than a barrel or a non-free-float handguard.

Free float handguards do provide a noticeable gain in accuracy, especially when resting the rifle on a barricade or using a sling. In other words, any time when we might be exerting some pressure on a barrel. Also, on an M4, we can’t get the longer, more useful handguard without free floating, and there isn’t much of a cost difference between free float and non-free float handguards, so there really isn’t a good reason not to go free float.

The low profile gas block makes life a lot easier, and means you don’t have to worry about burning yourself by touching the hot FSB. Daniel Defense does make a version of the RIS II that is 12″ long and has a cutout for the FSB. It’s a bit more annoying to install than one with a low-profile gas block. As long as it’s pinned in place, I’m cool with low profile for issue kit.

An improved flash hider is also welcome. The A2 ‘birdcage’ is a pretty good flash suppressor, unless you’re wearing night vision equipment. Then, it’s still pretty damn bright. So your own rifle is interfering with your vision. And people with night vision can find you easily. Not a problem while you’re fighting Taliban scum. Might be an issue if you fight a more formidable opponent.

I also really like coloring rifles not-black for issue purposes. It occurs to me that this could be done easily and cheaply with some Krylon and tape to keep paint off optics and out of muzzles, but the Army isn’t likely to go for that.

Unsurprisingly, I’m a big fan of the M4A1 PIP program, though I might like to see if other handguards are better (maybe one with mlok? It’s on the Army’s new HK CSASS). And buying new upper components and assembling them is a lot cheaper than buying M27s. And if you had a good PIP product, that would get rid of most of the reason for adopting the M27.5

As for the other question, is the M4A1 PIP better than the HK 416/M27, that’s likely to require testing that I can’t do here. And knowledge of what price I could get each for, which I don’t have. But within the confines of “For the US Army”, or another army that has already bought M4s, it’s almost certainly a better idea to upgrade.

Finally, some weight data if you’re interested in considering some of these rifles for your Infantry Kit Challenge.

CarbineWeight
Basic M46.120 lbs.
M4+RIS6.245 lbs.
Basic M4A16.80 lbs.
M4A1+RIS6.420 lbs.
M4A1 PIP6.990 lbs.
HK 416A5-14.5″ barrel7.678 lbs.
HK M277.900 lbs.

Weights in the above table assume no carry handle is mounted and the weapon is unloaded. I used the weight for the Knights Armament 600 m rear sight since I don’t have weight numbers for the Army-issue Matech 600 m rear sight. Both fold away when not in use. ‘Basic’ means with the plastic handguards. M4 assumed to have H1 pattern buffer. Front sight on the M4A1 PIP was assumed to be the Troy folding front sight. For improved muzzle device on the M4A1 PIP, I chose the B. E. Meyers 249F, since it has tested better than the A2 birdcage. HK 416A5 and M27 weights included for reference. Note that the M27 has a 16″ barrel, not a 14.5″ barrel like all others on the chart.

1.) It’s a pencil profile that’s been thickened in front of the gas block. First introduced on the M16A2. It is a stupid profile and I don’t like it.
2.) Later replaced with the KAC Rail Adapter System (RAS).
3.) It’s a 12″ long quadrail that’s free floated, pretty sturdy, and already in the US DoD’s procurement system, so they wouldn’t need an elaborate RFP/Eval/challenge process. It also allows the easy mounting of the M203 with existing brackets, since that lacks rail mount adapters.
4.) Okay, it’s not just about looking cool.
5.) Yes, I know the HK 416/M27 has a short-stroke gas piston. While this is easier to develop, the M4’s direct impingement system has got a lot of development time already sunk in. And I don’t see actual benefits from the data when you compare the 416 to modern M4s (or Mk 18s if you want to talk properly short barrels). More on this later.

Resurrected Weapons: Douglas F6D Missileer

We looked at the long-range, high performance Eagle missile on Tuesday. Now, let’s look at the plane to carry it.

As ever, the US Navy was concerned about saturation attacks on its carrier battle groups. To counter the new threat of bombers armed with large, long-range antiship missiles, the Navy had two projects under development in the late fifties. One was the Typhon long range SAM, with a projected range of 200 nautical miles. The other was the Eagle/Missileer project.

Missileer was, unusually for the jet age, a subsonic fighter. Given that it had to stay on station more than 200 nautical miles away from the fleet, and that more loiter time was significantly better, the decision was made to keep the design subsonic. Long loiter also conveniently sidestepped delays in interception from launching alert fighters, since the fighters could be orbiting and ready. Subsonic design made mounting a large, advanced radar and large, advanced missiles easy. We’ve already talked about the massive, 1,284 pound Eagle missiles. The Missileer was designed to carry six of them. It was also designed around the large APQ-81 radar.

APQ-81 was an early pulse doppler radar. In an era when a fighter radar with a 24 inch diameter dish was considered large, APQ-81 had a dish 60 inches across. It could detect a standard radar target1 at 120 nautical miles, and track sixteen of them simultaneously at 80 nautical miles. It had a track-while-scan mode. It was designed with innovative anti-jam features from the beginning, including a narrow, 3° beam with a 24 kHz bandwidth, both chosen to avoid most available jamming systems.

Unsurprisingly given that it had to carry such a large load, the F6D was fat and ugly. It was 53 feet long and had a wingspan of 70 feet. It was powered by a pair of Pratt & Whitney TF-30s, engines that would go on to power the F-111 and the F-14A.

Like the AAM-N-10, he Missileer was cancelled by McNamarra to free up budget space for other things. The aircraft itself would be easy to develop but the radar and systems integration (and the AAM-N-10) would be risky and expensive. Plus, they’re overspecialized for a single mission. The F6D had to be bought in conjunction with another, more conventional fighter, since it could not provide strike escort capability or establish air superiority. It was a project that was somewhat ahead of its time, like Typhon. The US Navy would later get a much more reasonable set of systems with similar capabilities in the 1980s with Aegis and Tomcat/Phoenix.

Verdict: Funding request denied by the Borgundy Aircraft Procurement Board


  1. In the late 1950s, the standard radar target was assumed to have a radar cross section of 5 square meters. This corresponds to the radar cross section of a B-47 bomber.