Thursday, February 14, 2019

Hyper Velocity Projectile Test

The Navy announced a limited test of hyper velocity projectiles (HVP; for a general discussion, see “Hyper Velocity Projectile”) fired from a 5” gun.  This is great news because the HVP can … can … ah …  Well, I’m not actually sure what the HVP can do.  No one has laid out an actual tactical use/benefit beyond vague generalities, most of which are likely untrue.

Last summer USS Dewey (DDG-105) fired 20 hyper velocity projectiles (HVP) from a standard Mk 45 5-inch deck gun in a quiet experiment that’s set to add new utility to the weapon found on almost every U.S. warship … (1)

Oh, now I see.  The HVP is “set to add new utility”.  That’s good.  We can always use new utility.  What the hell is new utility?

Here’s a bit more specific claim,

… the Navy could turn the more than 40-year-old deck gun design into an effective and low-cost weapon against cruise missiles and larger unmanned aerial vehicles. (1)

I fail to see how a faster projectile is going to transform the AAW-ineffective 5” gun into an effective AAW gun.  It’s still the same 12-15 round per minute rate of fire that’s considered too slow to deal with modern missiles.  It’s still the same train and elevation rates which are considered too slow to deal with modern missiles.  It’s still the same fire control system that is not considered capable of air-to-air gun engagements.

BAE Systems claims all kinds of amazing performance including 40-50 mile range, guidance, 20 rds/min from a 5” gun, high maneuverability, and low cost.(2)  As with any industry touted system, cut the performance in half and double the cost you’ll be somewhere in the real neighborhood.

You’ll recall that one of the original selling points of the rail gun was that it would fire inert, essentially free, projectiles … lumps of metal.  Well the 5” HVP isn’t going to be free.

… a hyper velocity projectile – even in the highest-end estimates have it in the $75,000 to $100,000 range, and that’s for the fanciest version of it with an onboard seeker. (1)

As you know, these kinds of estimates always wind up being understated so figure on doubling that cost.  That’s no longer a cheap projectile.  Yes, it’s cheap compared to a $1M-$2M missile but when you’re firing HVPs at 12-15 rds/min the cost quickly adds up.  At $100,000 per projectile (to use the likely optimistic number cost), firing for one minute will cost $1.2M-$1.5M.  Where’s the cost savings?  Unless the HVP transforms the 5” gun from a 0%, non-AAW-capable gun to something like a 90%, can’t miss weapon, there won’t be any cost savings.

Related thought:  If the HVP is all it takes to turn the 5” gun into a marvel of AAW weaponry, then why are we still wasting money on Standard missiles, ESSM, and RAM/SeaRAM?  But, I digress …

Here’s another suggested use,

HVPs could also find a home aboard the Navy’s Zumwalt-class destroyers as a replacement round for the classes 155mm Advanced Gun System. (1)

The Zumwalt’s 155mm Advanced Gun System (AGS) was intended to be a precision guided, land attack weapon with 70-100 mile range.  How is the HVP going to replicate that performance to be a viable replacement for the cancelled LRLAP?  It could, perhaps, someday, become a second rate, poor man’s replacement but it can’t match the LRLAP specs.  To be fair, the LRLAP couldn’t match the LRLAP’s specs!

What would the cost of a very limited production quantity, one-of-a-kind,  AGS-HVP munition be, do you think?  We’re looking at half a million dollars or more, quite likely!


(1)USNI News website, “Navy Quietly Fires 20 Hyper Velocity Projectiles Through Destroyer’s Deckgun”, Sam LaGrone, 8-Jan-2019,

(2)BAE Systems website, retrieved 8-Jan-2019,


  1. Honestly I am not sure the US can field a new 5in. Does anyone even remember how to build a naval deck gun...i mean look at the AGS....its just a missile launcher.

    I do remember one good gun MK-71 8in gun system. Would be interesting to see how a DDG51 or a Zumwalt handled one. or Two in the case of the Zumwalt.

    1. Just to be clear, the HVP is intended to be fired from existing 5" guns rather than design and build a new one.

  2. The rationale is that in the AAW role, guidance will mitigate the low rate of fire, but well, I wouldn't really put much stock in that. There's only so much steerable fins and a radar seeker can do for an unpowered projectile on a ballistic path, even one traveling at Mach 5. I think the real thing is in the quote, on how this is meant to be used against large UAVs; I'd rather fire 20 HVPs on 20 UAVs, instead of firing 20 Standards or ESSMs, because then I've still got my serious SAMs for dealing with serious threats. Using it against ASCMs I feel may be more of a "well, it can't hurt" sort of thinking.

    I'm a bit skeptical on the claims of 40-50 mile range; atm landbased 6" is topping out about 30-odd miles, and that's with long barrels and extra charges, meaning more barrel wear. There's also questions from a lethality standpoint because as we see with smart 25mm and 40mm grenades, the more electronics you have in the shell, the smaller your filler, and the 5" gun doesn't really have *that* much explosive filler to begin with.

  3. Conceptually, the HVP is akin to a sabot round that tanks use, right? Not saying we shouldnt pursue it, but I am not seeing anything magical here. Or am I off here?

    1. @Rob: Not a sabot; artwork of the HVP is that it's a full caliber projectile, just a lot more pointy and streamlined than existing 5" rounds. The idea is that it's a guided round that you can use for long-range bombardment and ASuW; from other news reports that I've seen it seems like land attack and ASuW is the primary intended application for HVP, with defensive AAW being something of a stretch role that the USN is exploring.

      The real magic in HVP is not in the shell shape, but in the electronics: the guidance package, the steerable fins, that sorta thing.

      To be fair, you'd need to have guided rounds anyway for long range bombardment. The effectiveness of unguided 6" artillery (155mm NATO/152mm Soviet) taps out at 40km (24 miles) because of dispersion from wind effect, which is why to get effective hits beyond that range you need guided rounds, else the CEP would be too high as to be useless.

      And that's with 6", which has better long range properties than 5", a smaller lighter shell.

    2. Anyway @Rob did some more reading on HVP to refresh my memory. Conceptually I'm seeing some parallels with the US Army's interim SHORAD Stryker config, where they use Longbow Hellfire as an anti-UAV weapon, as opposed to IR MANPADS like Stinger, because it's for use against UAVs that don't have enough heat sig for an IR SAM to track on, but Longbow Hellfire's got a millimeter wave radar seeker so it can lock onto things that don't have much of a heat sig.

      Seems to me like someone had the idea that since HVP is a Mach 3+ projectile with a mm-wave radar seeker, they might as well try and see how effective it is in an AA role, not just ASuW.

    3. I believe it is some kind of subcaliber projectile. The following info is from the BAE info PDF:

      Specifications Compatible with Mk 45, Advanced Gun System (AGS), 155mm Tube Artillery, EM Railgun Length Integrated Launch Package 26 inches Flight Body 24 inches Weight Integrated Launch Package 40 lbs Flight Body 28 lbs Payload 15 lbs.

      Notice the different weights for the "Integrated Launch Package" & "Flight Body"

  4. The concept is interesting and worth additional testing. I doubt such a weapon has the range and effectiveness of an ESSM. But, it certainly outrages CWIS and SeaRam so it could provide another layer of defense for AAW. And, could potentially be a cheaper alternative against slower moving helicopters or drones. I could also see such a round being used to defend against a swarm attack of small boats. With a guided round, it could be one shot-one kill.

    Though the cost will probably exceed $100,000 dollars a round, I'm not so worried about the cost as the Navy was able to bring down the cost down of the LCS (I know, not the best example). And, with the Excalibur round, the Army has been able to get the cost down to $66,000 a round per Wiki. With 100+ 5-in guns in service, that ought to be enough of a base to warrant a large enough buy to reduce the cost per round.

    Though, its probably too early to tell, I wonder how barrel life is affected. For example, does firing 100 HVP rounds equate to firing 1,000 convential rounds?

  5. I wish the Navy would develop some weapons for targets OTHER THAN CRUISE MISSILES. There's always a possibility of an enemy fleet including something exotic, like warships...

    1. Good point. The Navy's focus is a bit myopic. There are many target types out there that the Navy is largely ignoring. The Navy had to be dragged, kicking and screaming, into pursuing a Harpoon replacement.

    2. The AGM-158C LRASM should alleviate most of your concerns. It doesn't have the range of the Tomahawk, but it is cheaper and has an autonomous targeting system. Though most of the work has been getting it fitted to aircraft, it is compatible with the Mk 41 VLS.

  6. Why are they trying to make a missile out of a gun shell? The entire point of the gun is that its an economical jack of all trades master of none.

    Build a better tube with more longevity and/or RoF. Build a better turret with faster traverse and elevation. Build a better fire-control system for increased accuracy and versatility, upgrade the proximity fuses if possible

    but leave the shells alone. Upgrade everything except the shell. It's the same logic by which I have a state-of-the-art polymer handgun with trijicon night-sights firing a 9mm bullet that was originally developed in 1902.

    1. Because the 5" gun just doesn't cut it anymore for AAW work. Quoting ComNavOps from the text of the post:

      "I fail to see how a faster projectile is going to transform the AAW-ineffective 5” gun into an effective AAW gun. It’s still the same 12-15 round per minute rate of fire that’s considered too slow to deal with modern missiles. It’s still the same train and elevation rates which are considered too slow to deal with modern missiles. It’s still the same fire control system that is not considered capable of air-to-air gun engagements."

      15 rpm VT fuse was sufficient in WW2 against the IJN's prop aircraft inventory, especially when you had multiple 5" guns firing. But now with the Mk45 gun, it's just the one gun.

      From what I've reread about HVP, it appears that the primary intent behind the HVP's design and guidance package was for the land attack and ASuW missions. By adopting a low drag design that can hit Mach 3, you get increased range and shorter time to impact (it's a sliding scale towards either end). By giving HVP steerable fins and a guidance package, for the land attack mission this lets you exploit the full range you can shoot at and mitigates dispersion; for ASuW, HVP can now guide on a maneuvering target with better hit chance than an unguided round.

      And since it's a guided round with its own seeker, the Navy doesn't lose anything by testing it to see how effective it could be in the AAW role. Worst case it's a failure as an AA weapon, in which case the Navy hasn't really lost out because it's still gotten what it wanted out of HVP as a new land attack/ASuW weapon. Best case it works as promised, and then gives the warship an additional option for defense against incoming missiles.

      Also, I get the intent behind your analogy, but I feel it should be pointed out that modern 9mm ammo has also improved on the original 9mm Parabellum round, what with the better bullet materials and designs, and better powders that we now have.

    2. Also, while USD 100,000 is a lot of money in civilian terms, it's chump change for the US Military. Consider the Javelin missile, which the US Army hands out as a squad-level weapon. In FY2019 dollars, it costs 174,000 USD (i've seen a low estimate of 100,000). To date, over 45,000 Javelins have been built - if we take the low estimate of Javelin's cost, that's 4.5 trillion USD spent on Javelins. *shrug*

    3. Rate of fire and traverse/elevation speeds can be improved by improving the gun mount itself. Accuracy can be improved by addressing fire-control and the tube.

      OTOH; what is the point of firing a six-figure bullet out of a slow and inaccurate gun? That's like firing golden sabot shells out of grandpas' old break-barrel sawed-off shotgun.

      If 5in really is too dumb for AAA, too short-ranged for shore bombardment, and too slow for ASuW, then land the damned thing and use the deckspace for something relevant.

      Wunder-bullets won't make a bad gun-system good. Either update the system into the realm of relevancy..or kill the system.

    4. Wild Goose: Check your math. It should be in the billions and some of these missiles, about 10 to 15% from what I can estimate, were foreign sales.

    5. @Anon: yeah the fingers had a brainfart there. Still, my point was that illustrate that the US could indeed afford buying HVP and the relative lowness of the cost, given all the Javelins fired off in Iraq and Afghanistan.

    6. @Kirby: There's only so much you can do to improve the 5" gun, what with the physics involved. You can try increase ROF like Bofors did with the TAK-120, but that means dropping down to a lighter shell with less range.

      Also, even on land based artillery, people are looking into guided rounds for long-range shots, because with 6"/155mm, 40km (30 miles) is the limit of effectiveness for unguided rounds; past that range, you run into dispersion from wind effect, throwing your rounds off. Sure, guns that can shoot out to 53km exist today, but they're not as accurate at that range as they are at 40km, which is why they end up being used to shoot to 40km and the additional range isn't utilised (plus, faster barrel wear from more charges is also an ongoing issue).

      Is HVP going to be effective in AAW? I don't know. We'd have to wait and see how things shape out - the question is whether or not a guided projectile traveling at Mach 3 can mitigate the weaknesses of the Mk45 gun in AAW (or rather, mitigate sufficiently so as to make the Mk45 an effective weapon). I will note that my opinion on point defense is that to be effective, your interceptor projectile needs to be guided and capable of homing to the target, be it a point defense missile or a gun round.

      Something to also think about: at 100,000 a pop, HVP is more expensive than standard 5" HE, but if the USN buys enough rounds for all the DDGs and CGs - let's call it a magazine of 500 rounds per gun, DDGs have 1 gun, CGs have 2), that's 62 Burkes and 21 Ticos, 104 guns, and 52,000 rounds. That comes up to 5.2 billion, which would be undoubtedly cheaper and faster than designing a new gun and arranging yard time to refit said new gun onto the fleet - and it's likely the older ships wouldn't get the new gun either, given their advancing ages.

      Remember, your 9mm round you buy today has its own share of improvements from the first 9mm Parabellum round ever fired.

    7. "To date, over 45,000 Javelins have been built - if we take the low estimate of Javelin's cost, that's 4.5 trillion USD spent on Javelins."

      Incorrect math issues aside, many, many thousands of missiles have gone to foreign sales to the 20-30 countries that use the weapon. Further, the missile has been in production since 1996 so the cost is spread over 23 years or so. Subtracting, say, 5000 from the total production for foreign sales, that leaves 40,000 for US use which is an average of 1739 purchased per year. Using your $100k cost figure, that's an average yearly purchase cost of $174M - certainly not insignificant but not exactly earth shaking by US military budget standards.

    8. if the USN buys enough rounds for all the DDGs and CGs - let's call it a magazine of 500 rounds per gun,"

      As I said in other comments, it appears that the 5" round will be kinetic effect only with no explosive and no fuzing.

      A kinetic effects round is of limited use in land bombardment which, barring miracle AAW performance by the HVP, would be the most likely use for a 5" gun. A kinetic projectile has very little (no?) area effect. If it does not hit a specific target, it just buries itself in the ground. There is no area explosion and no shrapnel. A near miss is a complete miss. In contrast, a standard 5" projectile has an area effect due to explosive and shrapnel effects. It seems highly likely that the Navy would retain significant magazine inventories of standard rounds. The HVP would seem to be more of a limited use, niche weapon. Just speculation on my part.

    9. "certainly not insignificant but not exactly earth shaking by US military budget standards."

      We're getting a little too caught up in the details, I feel. I went with the oversimplified figures for Javelin to illustrate a point with regard to the total cost of all those Javelins. And you're right that 45,000 Javelins weren't bought in one go, but over a 23 year lifetime: the same thing applies with HVP. If HVP goes into full production, I don't envision the USN doing a mass buy of 52,000 rounds to refit all ships in one fell swoop, I think we're going to see what's been happening with SM-6 procurement: we're going to see regular yearly buys and the Navy is going to replace rounds at a steady pace.

      What's probably going to happen, I think, is that instead of for example buying 2000 HVPs to completely fill the magazines of 4 DDGs, we're going to see things like buying 2000 HVPs and allocating 100 rounds each to 20 DDGs, something like that.

      200 million USD a year isn't an earth shaking figure, afterall.

      "A kinetic projectile has very little (no?) area effect. If it does not hit a specific target, it just buries itself in the ground. There is no area explosion and no shrapnel."

      Yes and no; what happens with kinetic projectiles is that when you get to a certain velocity on impact, you're going to hit hard enough that there's still going to be massive force and pressure wave. The idea is to maximise your impact speed (i.e. fired out of a railgun at hypervelocity) and to maximise your mass (i.e. dense metal round made from DU) - and fun fact, if the round is going really super fast enough when it hits, it can turn into plasma on impact.

      But this is a moot point for 5" and 155mm HVP because traveling at Mach 3, the rounds aren't going to going fast enough to deliver that kind of force, so you _have_ to use HE. And the Army isn't going to buy these rounds rounds unless they can be sure that they can adjust the fuses to do impact and airburst - Raytheon's shopping HVP to the Army as well as the Navy...

    10. "We're getting a little too caught up in the details, I feel. I went with the oversimplified figures"

      This blog is all about data and analysis. Getting caught up in details is what we do! Analysis is what we do! Oversimplification is NOT what we do.

      Before you comment, verify your numbers and subject them to your own analysis. It will save me the trouble of doing it for you and deleting your comments as factually incorrect.

    11. "when you get to a certain velocity on impact, you're going to hit hard enough that there's still going to be massive force and pressure wave."

      At Mach 3, the HVP doesn't travel that fast. It's not even hypervelocity which is Mach 5 - Mach 8, depending on whose definition you choose. By the time an HVP hits, it will be traveling well under Mach 3. Kinetic energy is a function of mass and velocity and the mass is very small and the velocity, as noted, is relatively slow on impact. There is no massive force or pressure wave. A kinetic HVP that misses its target will simply bury itself harmlessly in the ground.

  7. Im not very knowledgeable about this, so bear with me... It Seems the consensus is that HV or not, the 5in is not a viable AAW tool... That being said, wouldnt a "dumb" HVP make the gun inherently more accurate due to lesser flight time and more resistance to wind, etc? That in itself seems worthwhile, although the issues of it packing a small punch and/or going right through thin skinned targets are still present, which then make the while idea relatively worthless... I just dont see the wisdom of a six figure 5in round...

    1. Whether the HVP is dumb or smart makes no difference to the round's flight time, because it's going weight the same; if you take out the guidance package that space is going to have more HE filler put inside it. Also, smart rounds have more resistance to wind effect, because you've got the steerable fins and can course correct for dispersion, which doesn't happen with plain dumb rounds.

      Also while HVP is a saboted projectile, that doesn't mean it's the same as tank APFSDS rounds. HVP is still a HE round; undoubtedly some HE filler has been sacrificed to fit in the guidance package, but it's not going to be like tank sabot and go through and through thin skinned targets.

      On one hand, 100,000 dollars does look like a lot of money, but think of it this way: every HVP you fire might cost you 100,000 dollars, but it's saving you some 2 million dollars on a missile that you're not firing, not to mention that you're keeping that missile in reserve for a target that really needs it.

      Shooting down a UAV with HVP, or hitting a small boat with HVP, lets you save Standard & ESSM for intercepting missiles, and saves you your LRASM and NSM for use on enemy warships.

    2. "but it's not going to be like tank sabot and go through and through thin skinned targets."

      Do we know this to be true? It's unclear to me that the 5" HVP is going to be contact or dispersion fuzed. In fact, from what I can gather, it's intended to be a kinetic kill round. If that's true, then it may well go straight through a think skinned target. For example, a small boat will offer no appreciable resistance and an HVP may simply pass through leaving only a 5" (or whatever diameter the actual round is) hole. This is the bullet-through-a-piece-of-paper analogy.

      I'd be quite interested in whatever evidence you have to support your statement. Please share.

    3. " every HVP you fire might cost you 100,000 dollars, but it's saving you some 2 million dollars on a missile that you're not firing,"

      Unless the 5" HVP turns out to be a magical 90+% kill weapon - and there is zero reason to believe that - then the costs add up very quickly at, say, 10-15 rounds per minute. If it requires 10-50 rounds to achieve a single kill (no one has any idea what's required), the cost is $1M-$5M per engagement. The cost savings evaporates quickly!

    4. "I'd be quite interested in whatever evidence you have to support your statement. Please share."

      According to NAVSEA's briefing slide, which is quoted as Figure 16 in the report "Navy Lasers, Railgun and Gun-Launched Guided Projectile: Background Issues for Congress", ( ), HVP is supposed to have a HE round for naval gunfire, when fired out of the Navy's 5 inch and the Army's 155mm artillery guns.

      AS for the cost issue, I think we need to look at that from several angles. On the effectiveness of the round: We know that milimeter wave radar seekers work - the Longbow Hellfire's radar seeker is good enough to track moving boats and UAV/helicopter type targets, for instance. GPS/INS guidance and steerable fins are also mature, known technologies. So, depending on the target it's aimed at, I think that there is the potential for HVP to indeed be an effective round. These are all known technologies that have been demonstrated to work in other applications, it's a matter of tying them into this one package.

      Also, monetary costs aside, there's also the consideration that having guided HVP rounds means that you've got deeper magazines to use against Chinese UAV baiting. The report raised the concern of unfavorable cost ratios, in the sense that you might spend 800k to 3.9 million USD on firing a SAM at a Chinese UAV that was built for a fraction of the price - and once you've used that RAM/ESSM/SM-6, you don't have it available for more serious threats.

      And as I've said before, for the land attack role, if you want to shoot beyond 40km, you've got no choice but to use guided rounds to mitigate dispersion. Spin stabilisation just won't cut it against drag and wind effect. That's the cost of doing business.

    5. "HVP is supposed to have a HE round for naval gunfire"

      The referenced slide is purely speculative and no explosive HVP currently exists, as far as I know. Further, the same slide indicates that the 5" HVP is, indeed, saboted and when the "average" projectile diameter is considered, the projectile is significantly sub-caliber. A standard 5" round has around 8 lbs of explosive. Given the extremely sub-caliber diameter of the HVP, the need to pack in a millimeter wave sensor/seeker, guidance electronics, guidance mechanics, fins, and fuzing, the room available for explosive will be very small. My guess is around 2-4 lbs of explosive.

      In short, I see no use for a land bombardment explosive HVP. HVP will likely be limited to kinetic application against known, fixed targets which are relatively few on a modern, fluid battlefield.

    6. "We know that milimeter wave radar seekers work - the Longbow Hellfire's radar seeker is good enough to track moving boats and UAV/helicopter type targets,"

      This is very short range tracking against almost motionless targets, on a relative basis. The short millimeter radar detection range is problematic for use in AAW when the convergence speed of the target and projectile may approach Mach 4-5. By the time the projectile is close enough to detect the target, the target is already past! Also, the time available for guidance maneuvering is almost zero. Unless the seeker can detect the target from much farther away, a guided AAW-HVP will not be any more effective than a standard 5" round.

      For example, at a combined closing speed of Mach 4, if detection occurs at 1 mile, the target will be past in 1.2 seconds. That's useless for guidance maneuvering. The question is what range can a millimeter radar actually detect an incoming missile? Given the extremely small size and low power output of a radar packaged into a sub-5" HVP, I'd guess that 1 mile detection is optimistic but I'm not a radar expert.

      Despite not being a radar expert, it is easy to see that developing an effective guided HVP for AAW will be challenging.

    7. It's my understanding that there are more than one kill mechanisms for tank sabot rounds vs other tanks:
      1) Mobility kills by taking out an engine or blowing off a tread.
      2) Penetrating the turret/crew compartments and tanking out the crew by spalling. The spall is basically the interior of the tank near the penetration point along with fragments of the penetration rod itself.
      3) The pyrokinetic effect of a depleted uranium perpetrator which superheats upon impact and can detonate fuel, ammo, etc.

      Applying these to ships and boats:
      1) mobility kills against the engine of a small boat or ship, say up to a patrol boat is possible. Against say a cruiser, it has a lot of inner bulkheads to go through and will probably fragment before penetrating far enough. the high velocity also means less time for the target to move and less leading the target. So a 5" may get swarm boat engagement ability if you are only expecting a mobility kill. IF the explosive in an HVP were a shaped charge then you might actually penetrate outer decks then do a kill deeper inside.
      2) Spalling against a graphite hulled ship would non existent and a thin hulled steel ship minimal. But it would be enough to take out a bridge crew on a steel/aluminum ship. But on a larger ship the CIC should be too deep in the ship for this to have an effect. Work as command crew killer vs smaller corvettes.
      3) Not sure if the HVP would have a pyrokinetic effect as I'm unsure of it's composition. But with an actual HE charge it would be the same effect.

      Does this assessment sound logical?

    8. "Does this assessment sound logical?"

      Not quite. The key is resistance. A bullet has incredible kinetic energy but passes through a piece of paper without expending any of its energy. It leaves a bullet sized hole but does no further damage because the paper does not offer enough resistance for the bullet to convert its kinetic energy to heat. The same phenomenon may apply to a ship and HVP. The HVP may simply pass through the thin skin of a modern ship and do nothing more than leave a couple inch hole! It depends on the degree of resistance. Beyond raising the question, I can't definitively answer it. So, will a HVP kill the bridge crew? I kind of doubt it. As far as a mobility kill, unless it hits a key component, again I doubt it. I also highly suspect that an HVP would pass clean through a small boat and do no damage unless hit just happens to hit a key component.

      Does that make sense?

      By the way, see the next post.

    9. Your new post renders all my speculation moot as the HVP is only a P at rifle velocities.
      I agree with you about resistance, it is key to both heat and spalling, especially spalling. But in the case of tank APDS vs APC--whose aluminum or steel is about hull steel thickness--it will take out the crew hence my believing that a corvette or larger bridge would be effected. Of course that also depends on equipment at the penetration point. if it goes through a window it would only scare the bejesus out of the crew and do no real damage.

    10. " if it goes through a window it would only scare the bejesus out of the crew and do no real damage."

      Don't underestimate the impact of urine-soaked underwear on combat efficiency!

  8. I am at a loss to understand why the Navy is continuing to try to make a small caliber gun into something it can never be; a heavy gun.

    For the same cost and weight the Navy can by 2 76mm guns which Leonardo has already developed a "fast" anti-missile guided shell. One gun will never encompass 360 degrees no matter how fast it can traverse. If the Navy wants to use guns for boats, drones, low speed missiles, then put a 76mm gun on each end of the ship.

    HPV is a bad idea for the 5" gun. Pretending a DD will get close to a hostile shore with a single 5" gun flies in the face of logic (but then we are talking about the Navy leadership). There is no way to make the gun a "heavy hitter". Replace it with a 76mm and about 300 rounds of ammo and we might be able to hit a flying target a few miles from the ship!

    I am in favor of research, but it must be based on a realistic goal and likely-hood of success. A 5" gun might be useful on a ship with several guns but a 'Burke is never going to be used for shore bombardment. Trying too develop a shell for that role is foolish. Historically, 5" guns are not very effective at sinking war ships, needing hundreds of rounds, with explosive warheads, to be effective. Missiles and torpedoes do a much better job, at longer range.

    In my opinion, I would like to see the Navy get rid of 5" guns on 9000 ton ships and use 2 76mm which already have the faster train and elevation, the guided shell, are less expensive to purchase and fire, and no one will blame the Navy leadership for not providing gunfire support with such a small gun.

  9. The failed rail gun concept resurfaced two years ago with a third acronym -- HVP for Hyper-Velocity Projectile. Salesmen claim this is the result of rail gun research, but these "sabot" rounds were developed during World War II. American T4 Velocity Armor Piercing (HVAP) ammunition became available in August 1944 for the Sherman tank's 76mm gun. The projectile contained a tungsten penetrator surrounded by a lightweight aluminum body and ballistic windshield, which gave it a higher velocity and more penetrating power.

    During the Vietnam war, US Navy ships fired 8-inch "super heavy" 335lb projectiles out to 18 miles and 112lb LLRB "arrow" projectiles at Mach 3.5 out to 41 miles! The MK-71 gun may not excite armchair dreamers, but its basic 260lb 8-inch round can deliver four times the explosive power two times farther than current 5-inch guns.

    HVP "arrow" projectiles are nothing new, but give up most their explosive payload for greater velocity and range. But for true anti-air, you want a larger projectile to provide a much larger burst area. Moreover, you want a SLOWER projectile to ensure an ideal bursting time for a missile that is incoming. The idea of hitting a bullet with a bullet is nuts, which is why CWIS sprays out hundreds of projectiles a minute in hopes one will hit something.

    The issue here: current naval guns just don't generate the profits the industry desires.

  10. Although some sources cite hull cracks and inaccuracy as the reason for the death of the Mk71, deeper digging refutes that, and point towards budgetary issues and the Navys missle-centric focus at the time. The prototype that was on USS Hull still exists at Dahlgren, and probably should be dusted off and looked at again. It could be a cure for the Navys gun deficit.For a minimal weight and space penalty,it seems like a no- brainer to give added punch, with fsirly proven tech.
    A couple fun facts... The Spruances and Ticos were all built to accept the Mk71 in the fwd position, and the 5" aft. It was considered for the Burke FltI but its height interfered with fwd visibility and was dropped from consideration. Also, the Mk71 ACCIDENTALLY sank a target ship, when the laser guided projectiles hit the laser reflection at the waterline. Sorry for digressing somewhat off topic, but this blog continually has me reading and researching...

    1. I would do a post on the Mk71 tests and the hull cracking myth but NavWeaps website has already documented it quite nicely.

      For those interested in the Mk 71 hull cracking true story, see:

      Mk 71

    2. I'm sorry to say that I don't believe there is any chance the Navy will use the 8" gun on a ship:(

      In my opinion, the next best choice would be a true 155mm based on a scaled down Mk 71. Advantages are a much smaller and lighter gun, being 1/3 the size of the 8" allowing a much smaller, and less expensive platform. The 155mm will allow the use of the common artillery shells, no development is necessary. Using a semi-fixed system, like the 8" will require no changes to the Mk 71, except scaling it down and, projectiles and powder charges can be optimized for the mission.

      I believe a ship of about 8000 tons would be adequate for 3 guns and 600-700 rounds per gun. Two guns could be easily fitted to a 6000 ton ship.

      The dis-advantage would be the need to develop the powder case, although, the scaled down 8" container may be just right.

  11. @KH Sadly i think youre right, in that we wont see another 8in go to sea. But I dont think all that much development of gun or ammunition would be necessary for the '71. We had the gun and multiple (guided!) rounds decades ago. Modern alloys and manufacturing could trim the weight if its truly necessary. Besides commonality of rounds with the Army, I dont see such a small incremental size increase as being worth the effort. Any upgrade from the 5" should be about maximizing the lbs of explosive delivered... And 8inch is where you get that, while still being able to generally put it in the 5" guns footprint...

  12. I have nothing against the LRASM, but a big gun (8 inches and up) would be more versatile, and more cost-effective (you can buy a thousand shells for price of one missile).

    America is obsessed with trying to win at stand-off ranges, because of risk-aversion, but targets need to be identified, as well as detected. That's why fighter jets can't get rid of their guns, all these decades after missiles made them obsolete. Real fights tend to be close up. Volume of fire is still important.

  13. To be fair, I dont think its an American "obsession" to fight at stand off range. Sure we dont veiw our sailors as expendable assets, and act accordingly. But realistically who wants to fight fair? The ideal weapon is one that kills the enemy for you while being outside their offensive range!! Chinas "carrier killer" missle being a great example(without questioning its actual effectiveness, just using its premise as an example) The last thing any rival wants is to be inside a CVBGs strike range! So theyve come up with a standoff...

  14. It's an obsession, inasmuch as it comes at the cost of accomplishing stated goals, such as shore bombardment, amphibious assault, etc. We don't use UAVs because they're more effective than manned aircraft (they're not), but because we're reluctant to risk pilots to win a war. Target discrimination suffers, "collateral damage" mounts, we lose the moral high-ground.

    1. You're both correct and are, more or less, saying the same thing in different ways. Of course we want to stand off and destroy the enemy with impunity. However, we also stand off due to risk aversion rather than combat efficiency. Steven's point about shore bombardment and amphibious assault is spot on. We have doctrinally moved our assaults out to 25-50 nm not because of combat effectiveness (in fact, this doctrine has rendered our amphibious assault capability invalid) but because of risk aversion. The Navy has forgotten that was is all about calculated risk. The spectrum of risk runs from reckless to calculated to timid. You want to operate in the calculated risk region. Today, the Navy operates in the timid region, to the detriment of mission accomplishment.

      You're both right. You're just discussing different aspects of it.

    2. Points taken... Maybe risk aversion has more weight than I realize. I think that this is a continuation of the sword/spear/bow evolution, in that we have always pushed to have the next iteration,(although i believe that in the last century smaller losses are a byproduct, rather than focus of designing a superior weapon) and since WWII, we have. After having shifted focus from near-peer for so long, we lost that edge. Sadly, until (if?) we regain that, we are going to have to take on more risk to win...

  15. This story may have been regarding the Barrage Round. Although these hypersonic rounds look similar to their more expensive guided cousins, we have been testing fairly inexpensive GPS guided versions since around 2002.
    One of those tests took place in one of our local missile ranges. That round was actually completely unguided with the goal of smart guns and dumb but accurate long-range hypersonic shells. It also tested what is essentially armor-piercing shrapnel.
    Here is a story about one such test.

    1. Both of the rounds discussed in the article are fragmentation rounds and the one was a sub-caliber round, at that. I suspect that the explosive destructiveness of the rounds is minimal. Frag is great against soft targets but only marginally useful against armored or fortified ones.

      We can get thousand mile rounds if we're willing to reduce the round to the size of a 0.50 cal bullet and a 1 gram warhead but that wouldn't be combat-effective. I fear that our obsessive pursuit of range is blinding us to the fact that we're sacrificing destructiveness to achieve it.

      I'd rather have an utterly destructive 16" battleship round with only twenty mile range than a sub-caliber 5" round with infinite range but little destructive power.

    2. Very true. The Barrage Round is a sabot and a fragmentation round. The explosive destructiveness is minimal.
      In fact, the detonation is only intended to disperse projectiles that are effective against light armor, such as the tops of tanks, and against troops and regular vehicles.
      The beauty of it is that these are not necessarily guided, so many may be fired without massive cost.
      You are preaching to the choir about Battleships. This is what happens when the only platforms available are thin-skinned ships with small guns. However, even if we had Battleships, I believe such rounds would be a good option to have when surprise is needed or a target shows up that is out of range of regular shells.

    3. "I believe such rounds would be a good option to have "

      The more options the better! Too many people argue for or against any particular weapon system as if it's the only one we'll have and that's absurd. Options grant flexibility and flexibility promotes victory.

      The only thing we need to be careful of is that we don't continue to pursue range over destructiveness, as we seem to be doing. You clearly understand that but I fear Navy leadership does not.


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