Tag Archives: militariana

M4A1 PIP vs HK 416A5

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We talked a little bit about the M4A1 PIP before. Let’s compare it to the popular and successful HK 416A5.

The 416A5 is the latest variant of HK’s version of the M4. It’s available in a number of barrel lengths, but to try to keep this comparison as objective and direct as possible, we’re going to compare carbines with the same barrel length: 14.5 inches.

While the 416A5 is a production weapon, the M4A1 PIP isn’t. So I’ll have to make some guesses as to what it might have looked like in an approved format. In the above article, I made some guesses:

  1. “SOCOM” profile (a medium profile) barrel
  2. Safe/Semi/Full Auto Trigger Group
  3. Daniel Defense M4 RIS II (12″)
  4. Cut down pinned gasblock (as on Colt 6920-OEM2)
  5. Knight’s Armament folding front and rear backup iron sights
  6. H2-weight buffer
  7. B. E. Meyers 249F flash suppressor

Pretty simple. I chose those parts because all of those have NSNs, and are already-approved accessories, and Colt already makes guns with that particular low-profile gas block. I keep going back and forth on the notion of changing the stock, and settled on not changing it mostly to keep things simple. The obvious stock alternative is the SOPMOD stock, however I couldn’t find anything on stock changes, so I opted to be simple and leave the existing stock. The SOPMOD stock weighs 11.5 ounces, which is about 4.4 ounces (0.275 lbs) more than the regular stock.

Let’s compare them. Both carbines are capable of semiautomatic and fully automatic fire. Both carbines do not have a burst feature. Both carbines have collapsible stocks. Both carbines offer quadrail handguards. The M4A1 PIP has a 3″ longer handguard (12″ compared to the 416A5’s 9″ handguard), but both are longer than the 7″ RAS/RIS handguard currently present on the M4.1 Both fire the same 5.56×45 mm round.

Doing a weight comparison, the M4A1 PIP weighs 6.99 lbs as above, unloaded and without optic. The 416A5 weighs 7.68 lbs unloaded and without optic, which comes to a weight difference of 0.69 lbs. Where does the weight difference come from?

Both rifles have medium-profile, 14.5″ barrels. The 416 also has a short-stroke gas piston system and a heavy handguard, both of which add weight. The stock of the 416 is also a bit heavier.

Carrying more weight sucks. But weight can also bring advantages. Bearing in mind the following destructive tests had a sample size of one, let’s see what weight helps with.

On a standard M4, firing 140 rounds rapidly and continuously will raise the temperature of the barrel to the cook-off point. At this temperature, any live round remaining in the chamber for any reason may cook-off (detonate) in as little as 10 seconds.

What if you keep going cyclic? What if you’re desperate? Colt tested this in 1996, and discovered that the barrel on a standard M4 (with full auto trigger group) will burst after 596 rounds fired cyclic. That’s just under twenty magazines worth of rounds. That is a lot.

The M16A2 (also with a full auto trigger group) was also tested to destruction. Its barrel burst after 491 rounds. That’s also a lot, though less than the M4.

The M4A1 with the heavier SOCOM-profile barrel will fail after it has fired 840 rounds cyclic. In this case, the barrel won’t burst, but the gas tube will fail. If this was a problem, you could conceivably use a beefier gas tube. Or accept that this is good enough, since a soldier’s basic load is 210 rounds.

Unfortunately, I can’t find much in the way of good data on when the HK416 (or the M27 for that matter) fails if it’s run cyclic until it chokes. I do know that it’s “more than 900 rounds” but that’s the best I’ve got. This makes sense: the barrels are similarly beefy, and eventually the op-rod/piston will fail. Or the barrel will. Waste heat sucks.

So what do I think? Well, a good part would depend on what price you could get both guns for. But if you could get the M4A1 PIP as a package from Colt for any price that isn’t exorbitantly over that of the 416A5, I’d probably go with the M4A1 PIP. I like less weight, and I really don’t think the piston system gets you all that much for your trouble.

That goes triple if you already have M4s/M16s in your procurement system, since you can just swap uppers (and trigger groups if you have that infernal burst mechanism).

  1. We could have used a 9″ quadrail on the M4A1 PIP, but that would have increased its weight advantage, and we would have had to pick a handguard that isn’t currently in the inventory. The DD M4 RIS II 12″ handguard is already in the system, as the handguard for SOPMOD Block II upper. Also, note that I don’t have a weight figure for a 416 with an extended handguard. ↩

Unmanned Autocannon Turrets

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There’s a big interest in remote weapons stations for machine guns, since they let you use the guns without exposing yourself to enemy fire. Their bigger brothers, unmanned autocannon turrets, are also increasing in popularity, because they’re a cost effective way to add firepower to vehicles. Let’s look at some options. Alas, costs are unavailable, so you’ll just have to guesstimate.

EPOCH
First, Russia’s Epoch turret. It’s used on the T-15 Armata Heavy IFV, plus the Kurganets IFV, and could probably be retrofitted on to other things. It’s got a 30×165 mm autocannon with 500 rounds of ready ammunition (dual feed with one 160 round box and one 340 round box), a 7.62x54R mm machine gun with 2,000 rounds of ready ammo, and four Kornet-EM ATGM tubes. The gunner has a day/thermal sight with laser rangefinder. The commander has an independent day/thermal sight with laser rangefinder as well. I do not have information on whether or not these are Gen 3 thermal sights. No secondary remote weapon station is fitted for the commander. Epoch is not protected against autocannon fire. It is fully (i.e. biaxially) stabilized. Eight smoke grenade launchers are fitted. It is capable of high-elevation fire. It does not appear that reloading the turret is possible from under armor. Also, even though it lacks armor, given it’s bulk and ammo reserves, I would expect it to be heavy. Also, relatively expensive. But it does have the most firepower of any turret on our list.

MCT-30
This is the turret that the US Army is fitting to some of its Stryker vehicles for more firepower. It’s made by Kongsberg, out of Norway, and it has a lot of options. The gun is a 30×173 mm autocannon, with 150 rounds of ready ammunition (dual feed with a pair of 75 round boxes). There’s also a coaxial 7.62×51 mm machine gun with 600 rounds of ready ammo. ATGM launchers are available as an optional extra. The gunner’s sight is the usual day/thermal with laser rangefinder. An independent commander’s sight, or a Commander’s Remote Weapons Station, are available as optional extras. The basic turret has negligible protection, but the turret can be provided with protection against up to 30 mm autocannon rounds (STANAG Level 6) as another optional extra. High-angle fire is another optional extra feature, as are threat detection systems and active protection systems. All versions can be reloaded from under armor. We’d expect weight and cost to vary significantly based on desired feature set. It’s not a bad turret, but we wish it could accommodate more autocannon ammunition. A pity that’s not another optional extra. Full stabilization is standard.

Samson RCWS-30
This is an Israeli turret, currently in use on the Czech Pandur II. It’s very barebones, without any kind of protective shell. It comes with 200 rounds of 30×173 mm (in a 140 and a 60 round box), a 7.62×51 mm machine gun with a 460 round box, and a pair of tubes for Spike ATGMs. The turret is fully stabilized and a commander’s independent sight is available. A commander’s remote weapon station is not available. There are no protection options available for this model. On the other hand, it’s only 1,400 kg ready to fight. Also, since it’s an exposed gun and feed systems, it can be fitted with any other autocannon system. Conceivably, one could also increase the ammunition capacity, but that might require more powerful traverse and elevation motors. It is capable of high angle fire as well. This is probably my favorite turret from an ‘add more firepower’ standpoint, since it’s light, cheap, and provides balanced firepower.

Lance-RC
The unmanned version of the German Lance turret, the -RC variant is very nearly identical to the turret mounted on the Puma. It comes with a 30×173 mm gun with 200 ready rounds (dual feed, but I haven’t found box sizes), a 7.62×51 mm coaxial machine gun (probably about 650-700 rounds based on the Puma’s capacity for 5.56), and the option for a pair of Spike missiles. It’s got STANAG Level 6 protection out of the box, and excellent optics for the gunner and an independent sight for the commander. It can also be fitted with additional cameras to improve situational awareness or a laser-based jamming system as part of a soft-kill APS. As you might expect, it’s heavy and expensive. But it’s also very nicely equipped.

Of the NATO compatible turrets, what you’re trying to do will determine which you buy. Platform and transportability requirements will also impact your decision.

Leclerc Review

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The Leclerc is a very underappreciated tank. For better and for worse, it got its design completed just before the end of the Cold War. On the one hand, this is bad, because order numbers were slashed, and there weren’t large quantities of surplus tanks to drive the price down in the 90s, when no one in Europe thought tanks were cool.1 On the other hand, it meant it got a lot of really innovative design features pretty early. It’s still a formidable and competitive tank today, held back only by the lack of upgrade budget.

The Leclerc was designed to (finally) replace the venerable AMX-30, after a joint Franco-German project and the AMX-40 project had both failed. The French were the first western power to put an autoloader in a production tank. It’s a ‘belt-type’, and is contained in the turret bustle. It has a capacity of 22 rounds. A further 18 rounds are stored next to the driver in the front of the hull. The bustle is provided with blow-out panels. All ammunition is marked with a barcode, so that the autoloader knows what round types are where.

The gun is a 120 mm L52 smoothbore, developed in France. At the time of introduction, this was the most powerful tank gun in production. It can keep up with the newer Rheinmetall L55 given appropriate ammo design. The gun is fully stabilized.

In a reverse from other western designs, the coaxial machine gun is a 12.7×99 mm HMG, and the commander’s gun is a 7.62×51 mm GPMG. In its original design, the commander’s machine gun was pintle mounted. More recent improvements have replaced it with a remote weapons station mount.

The Leclerc was an early adopter of the Commander’s Independent Sight, giving the commander the ability to use optics to look in a direction other than where the turret faces. The Leclerc was also one of the first tanks to give the commander his own laser rangefinder in the sighting unit, an ability still not found on the Abrams or Leopard 2.

Leclerc came with a battle management system from the factory, though it initially did not have a video display. This was rectified on later models. Just like on other modern tanks, a battle management system provides a huge coordination bonus to vehicle crews and unit commanders, and just like on Abrams, the BMS on Leclerc is integrated with the communications suite.

Leclerc’s protection hasn’t been as upgraded as much as its contemporaries, and here it suffers. The best estimates I can find give it a protection somewhat less than an M1A2 SEP or a Leopard 2A6/2E. Given the era, it’s not terrible, but it could use some work today. It’s an interesting armor array because it uses a lot of materials chosen to reduce weight but are somewhat more costly to work with.

The protection of Leclerc is somewhat improved by the inclusion of the Galix combat system, which is a computer controlled array of 14 smoke grenade launchers. Current modernization plans increase this to 24 launchers. These are capable of launching the usual smoke grenades in quick-blooming and long duration versions, but can also launch antipersonnel grenades. While this system would make an excellent soft-kill component of an active protection system, I do not know of any plans to link it with a missile approach warning system.

Leclerc’s powerplant is my favorite part of the tank. It’s a diesel engine, but it’s a little bit different. Instead of a conventional V-12 diesel with twin-turbochargers, it has a 16.4L V-8, called the V8X, and its equipped with a hyperbar system. The hyperbar system is neither a supercharger nor a turbocharger. Rather, it’s an externally-powered compressor, driven by a small gas turbine engine. This yields absolutely massive boost pressures of 32.1 bar mean effective boost pressure, no turbo lag, and no loss of power at the driveshaft. It also yields big gains in horsepower. For comparison, the V8X generates 1,500 hp, and the same basic engine with a conventional twin-turbocharger instead of the hyperbar system generates 1,000 hp.

This come at a cost of course. You might have guessed the V8X engine is expensive, and it is. The hyperbar system adds quite a bit of bulk, though the gas turbine can also be used to drive an integrated APU quite easily. Finally, there’s the question of fuel consumption. The then brand-new Leclerc didn’t fare so well in the Swedish tank trials, though GIAT hadn’t really done much optimization of the engine settings. Once they had, the result was probably about what you might expect: better than gas turbines, worse than diesels.2

So what do we think? Well, that depends on the timeframe. Today, the Leclerc is good but in need of some upgrade funds, and the reduction of orders from 1,400 to 460 didn’t do anything kind to the price. But at its debut it was extremely modern, introducing a number of new features that were on the Want List of every modern tanker.3

  1. Looking at you, Leopard 2. ↩
  2. The numbers I have are about 4.5 L/km in M-1 and T-80, >3 L/km for more modern experimental gas turbines like the LV 100-5, about 2.8 L/km for the V8X, and 2.2 L/km for Leopard 2A6. I think newer diesels are supposed to get a bit under 2 L/km. Of course, I don’t have acceleration data for any of these vehicles. A drag race would be very illuminating. ↩
  3. Look at some early 90s vintage issues of ARMOR magazine, especially the ones from 1993. Plenty of great tank designs in there. Or look at K2. ↩

Abrams Additions

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Earlier, I talked about the US Army’s latest improvements to their Abramses, the M1A2 SEP v3 program. Which is great, because as they start to take deliveries, I’ve heard no concrete orders for further Leopard 2 upgrades, or anything about the vague, pie-in-the-sky new MBT to be developed by France and Germany. Given that it’s multinational, it will probably be overbudget, late, and contain a bunch of stupid compromises. So good on you, US Army!

This program, combined with the M829E4 APFSDS round development, plays to the traditional strengths of the Abrams: well designed armor piercing rounds, heavy frontal armor, and excellent fire control.

Unsurprisingly, I am not satisfied. There are a few more things I’d like to see in the short term. No, these aren’t dream weapons like a rail gun. These are doable things. They are in order of urgency (and also affordability, amusingly enough).

  1. An Active Protection System. Since this term gets kicked around a lot, I mean a proper hard-kill one. CIWS for a tank. There are a lot of good options. The US Army is currently “investigating”. Yawn. They should have a competition and pick the winner. Or just take Trophy, because it works pretty well at stopping incoming RPGs and ATGMS. No, it won’t stop APFSDS rounds. Oh well. Yes, it can be dangerous to nearby infantry. It’s not perfect. I don’t care. It works, and unlike a lot of other systems, it’s been combat tested, and a bunch of bugs have been beaten out of it. So what I’d really like is to just add Trophy. Plus the cost is reasonable. That whole “in production now” thing really helps with that.
  2. Extra roof protection. This isn’t too terribly difficult to add, but you’d need to do quite a bit of reworking, and probably add a power-assist to the hatches. Weight is also a concern. To be clear, we’re looking for a specific, limited protection upgrade. We want roof protection from DPICM-type submunitions, and maybe EFP submunitions if practicable. It is not feasible to protect against top-attack ATGMs with armor, so we won’t try. On the one hand, all those optics are toast in a submunition storm. On the other, we can at least keep the crew alive, and they’re more important. Tanks are reasonably easy to salvage. Crews, not so much.
  3. New engines. I’m not going to spill a lot of ink here, over type. You could give the existing, worn AGT-1500s a rebuild. You could (at least in theory) use the LV100-5 from the canceled Crusader program. You could switch to diesel. Given a diesel engine, you’d have to rework the rear suspension to remove the last set of torsion bars. You’d have two off-the-shelf engine choices:1 L3’s AVDS-1790 1,500 hp variant and General Dynamics’ GD883.2
  4. Situational Awareness improvements. The Germans have prototyped day/thermal camera arrays around the turret to improve situational awareness while the crew is buttoned up. Given the new 1080p displays added in SEPv3, these would be welcome and helpful, especially in urban settings. A radar or other missile approach warning system would be nice too, but that would come with the active protection system.

So there you have it. A few more ways to put more improvements into your M1A2 SEP v3 Abrams tank. I know Big Army is working on number one as I write this.

  1. Using the reasonable constraint of “1,500 hp diesel engines that are made in America” ↩
  2. A license built MTU MT833. Made in America so the Israelis can buy them with US Aid credits and use them in Merkava IVs. ↩

Rampant Armata Speculation

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Let’s have some fun with rumors, speculation, and armchair analysis, shall we?

We don’t know very much about Russia’s new tank, the T-14. In my review, I made the tacit (and completely groundless) assumption that the turret shell concealed some heavy protection for the gun. Something tank-like, i.e. that the frontal armor of the gun could be expected to withstand APFSDS rounds as well as big, high end ATGMs. Like the front of the turret of a Leopard 2A6/-A7/-E or an M1A2.

Let’s try to poke at this assumption a little, shall we?

First off, let’s forget about side protection. No tank in existence can take a modern sabot round to the turret flank and not care. Focus on the front. Clearly, the outer “shell” has negligible protective value. It does hold a lot of systems, most of which are fragile. Of course, there’s nothing else behind the turret face, so hits there will probably tear straight through the fragile sensors and APS effectors. The gun mantlet is not readily apparent, and the outer shell seems to be in the way. Compare the M1A2 and the Leopard 2A6, both of which have big, thick mantlet armor atop and around the main gun. This is curiously absent from the T-14.

Remember, composite armors trade weight for thickness especially when compared to an equivalent mass of steel. So if we want to stop sabot rounds from a tank, we’re going to need a bunch of bulk. And since we’d like to be able to elevate and depress our gun, we’re going to expect to see quite a bit of exposed, movable bulk.

We can also find some images showing a T-14 turret mounted on the relatively light (28-30 tonne) Kurganets APC hull. So there’s at least one lightweight version of the turret out there. Of course, the shell could hide more armor on the T-14 version, maybe. We can’t rule out two versions. Now, it’s hard to figure out how one could hide bulky composites under the shell, given its shape and attachment methods, but we really can’t be sure about anything. The Kurganets hull is a little unusual if only because this idea has gotten very little traction elsewhere. The Swedes have a CV90 version with a low-pressure 120 mm gun prototyped, but have not ordered it and have not achieved any sales. The US Army has a version of the Stryker with a 105 mm gun and autoloader, but this version hasn’t been too popular. The US Army has moved to add more conventional autocannon firepower to some Stryker APCs to get more firepower in the Stryker Brigade Combat Team. So no one else really likes this concept.

We should also note that T-14 has a lot of active protection system effectors. There are ten tubes for the Afghanit hard-kill APS, five on each side of the turret. Additionally, there are two boxes of twelve soft-kill (likely some kind of obscurant) effectors facing outward, one box on each side of the turret, and another twenty-four soft kill effectors in a vertically configured box to protect the roof. That is an awful lot of active protection.

For comparison, the Merkava IV has a Trophy (hard-kill) APS launcher on each side of the turret. Each launcher holds three effectors. No additional soft-kill system is mounted on Merkava. Of course, Merkava IV is also heavily armored, and Trophy is seen as a supplement for flank protection against high-end ATGMs (e.g. Kornet).

So what might this mean? Well, we know that the T-14 has a bigger hull than T-72. Scaling comparisons will tell us this. Also, we know that we have to fit all three crewmen up front, so that front compartment must be significantly bigger to accomodate the three crewmen plus all of the displays and computers. Also, loads of hull armor, since the front appears to be quite thick (it’s sloped, and likely some kind of composite or composite + ERA, all of which takes space). We don’t actually save all that much room in the turret basket, since we still have to have some sort of (probably vertical) carousel for enough rounds to make all this worthwhile. And while the engine is a weird X-configuration model, it’s quite a bit more powerful than the one on T-72, and it still needs a radiator, transmission, and of course fuel. So we’d expect the hull to be noticeably bigger, and this agrees with what we can see from playing with scaling.

We also know that while the T-14 is heavier than the T-72, it’s still a light MBT. While it’s hard to draw comparisons to Western analogues, we do note the large hull and thick glacis armor would eat up a lot of mass.

Historically, the Russians have been quite strict about the weight of their tanks, simply because their infrastructure can’t take the weight of big Western tanks.1 For this reason, they pioneered the autoloader in the 1960s, and made heavier use of ERA than anyone else. Both are lighter than their respective alternatives. It’s quite possible that something had to give to keep the weight within tolerances, and the designers chose to accept a less well protected gun. Active protection systems are pretty good at defeating ATGMs, and they’ve made sure to have something for both direct-attack and top-attack weapons. In the current small wars, they’re not likely worried about sabots.

Further, the roof seems like it would blow-out in the event the ammunition storage compartment is compromised, and there are a pair of blow-out panels on the T-14’s belly. So ammunition cook-off will not likely kill the crew. Further, the Russians have put an escape hatch on the floor of the crew compartment. Good for them.

Could Afghanit be effective against sabot rounds? Specifically, the kind of APFSDS rounds fired by a modern tank gun (120 or 125 mm). Again, we can’t know for sure. It might be possible. But I’m disinclined to believe the present statements about it. Afghanit looks to shoot some kind of fragmentation or mini-EFP warhead to damage incoming projectiles. It’s simple and cheap, and works great against RPGs and ATGMs. But these are relatively fragile. An APFSDS round is a solid rod of some dense alloy (based on depleted uranium or tungsten), and it’s moving a lot faster than a missile.

It’s certainly not impossible to intercept an APFSDS round, but it’s a lot more difficult than intercepting a rocket. And the extent to which you disrupt it is important. You intercepted it. Great. What’s the effect? Is it destroyed? Damaged? Destabilized? If the round is still incoming, how much armor is needed to stop it? And what was the incoming speed and penetrator design? Test details are, naturally, hard to find. So color me skeptical that Afghanit can reduce the effectiveness of modern APFSDS rounds2 sufficiently for a lightly armored turret3 to be able to stop them.

Okay. So what do we think? Given the large amount of active protection systems, the reported wait, the size of the hull, and the nature of the turret shell, I think it’s quite possible the Russians are taking the T-14 in a new direction with a less protected main gun. They’ve pushed the envelope before. Some things have caught on, some things haven’t. This isn’t a notion I’m overly fond of, but that’s ok. The proof is in the combat, and the Russians will likely get into some before too long4. The keen observer might then be able to learn something as to whether or not these ideas work.

  1. I pick on Leopard 2 and Abrams enough, so let’s talk Challenger 2. Wouldn’t want the British to feel left out. With their “Streetfighter” Urban Warfare supplemental armor kit, the Challenger 2 tips the scales at 75 tonnes. ↩
  2. To be clear, I mean M829A3 or M829A4 depleted uranium APFSDS rounds fired from the M256 gun on an Abrams or the DM63 round from the Rheinmetall 120 mm/L55 gun on the Leopard 2A6 and subsequent models. Modern rounds, modern guns, no reduced-power charges. We never know what ad copy means, but that’s what you think of when I say “tank rounds shot at Russian tanks,” da? ↩
  3. Supposing the T-14 turret is lightly armored, that. But I suppose we should still define things, so something meeting STANAG 4569 level 5 or 6. In plain english, something ‘resistant to 30 mm APFSDS rounds”. ↩
  4. Unlike some other countries, the Russians are likely to get into a fight and test their new stuff. ↩

Armored Vehicle Fuel Capacities

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I’ve found these to be quite hard to find on the net. All do not include supplementary drop tank options. Except where specified, variants have the same capacity of the original.

VehicleFuel (US Gal)Fuel (L)
M15051,907.6
M1 with UAAPU4501,703.4
Leopard 2317.01,200
Challenger 2420.61,592
Leclerc343.41,300
K2342.41,296
Namer369.81,400
Merkava IV369.81,400
T-72264.21,000
T-80B486.11,840
T-80U467.61,770
T-90317.01,200
T-14426.61,615
M2197745.7
CV9030/CV9035221.9840
SPz Puma237.8900
ASCOD227.2860
Boxer MRAV145.3550
BMP-1122.0462
BMP-2122.0460
BMP-3184.9700
M11380302.8
M113A195359.6
Marder 1172.2652
Stryker52.8200
BTR-8079.3300
BTR-9079.3300
M270163617.0
M109135511
2S1145.3550
Panzerhaubitze 2000264.21,000
K9 Thunder224.5850
Centauro137.4520
G6/G6-52/G6-52L184.9700

IFV Autocannon Ready Ammo Capacities

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I mentioned this already in Bradley Planned Improvements, but it’s easier to find if it’s separated into a nice reference post. Also added information for the Stryker with Kongsberg MCT-30 unmanned turret.

IFVReady CapacityCaliber (mm)
M2A3 Bradley30025×137
M2 – 30 mm conversion18030×173
M2 – CT40 conversion9340×225 CT
Stryker with MCT-3015030×173
CV90402440x364R
CV903016030×173
CV90357035×228
Puma20030×173
K2122440x364R
BMP-250030×165
BMP-350030×165
T-15/Epoch turret50030×165

Some notes on the above:

  1. I’m defining “Ready rounds” as “rounds from which you can fire without manual loading”, since these are autocannons. So the CV9040 gets the quick-access rounds counted as ‘stowage’, because someone has to grab them and refill the 24-round ready feed system (three eight-round racks).
  2. The K21 gets credit for 224 rounds because the 200 rounds it has under the turret basket are connected to the gun via an automatic resupply system. No manual top-off required.
  3. Russian IFVs do not have any additional autocannon rounds stored separately in a non-ready condition. I.e. ready capacity is all you get.
  4. The “Bradley 30 mm Conversion” listed uses the existing 2-man turret suitably modified to accept the new gun and ammo. There’s also images of a Bradley with the turret crew moved to the hull and what appears to be an MCT-30 unmanned turret mounted in place of the original turret. It will match the Stryker/MCT-30 for ready ammo capacity.

Resurrected Weapons: M4A1 PIP

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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.

The USMC Moves to Issue the M27 to All Riflemen

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See: https://www.fbo.gov/index?s=opportunity&mode=form&id=278024299180d7a9c1185936329ae560&tab=core&_cview=0

This would be step one of the process to getting a whole bunch of them. One for every rifleman in the Corps.

Now, there are more steps that have to be done (an RFP), but this is step one of a procurement move.

And it’s pretty big. I know lots of folks who’ve been wanting to go this way, and HK originally called the 416 the “HK M4” until they ran afoul of trademark rules.

We’ll see if any snags come up. But this is an interesting move with the Corps.

Glad to see we agree again.

Resurrected Weapons: Douglas F6D Missileer

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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. ↩