Saturday, February 16, 2019

HVP Speed Lie

As you know, the Navy has, for the moment, shelved the electromagnetic rail gun in favor of firing hyper velocity projectiles (HVP) from 5” guns.  The HVP’s distinguishing characteristic is its speed which is reported to be Mach 3 (3344 ft/sec).  This leads the manufacturer, BAE Systems, to make all sorts of amazing claims which, if they are to be believed, would mean a single 5” gun is the only weapon any ship will ever need!  I’m being a bit facetious, here, but not much.  BAE and the Navy claim the HVP will handle land attack, anti-surface, AAW, and ballistic missile defense!

By the way, hyper velocity is defined as greater than Mach 5-8, depending on what definition you choose.  Mach 3 is not hyper velocity.  Moving on …

Let’s take that distinguishing characteristic, speed, and check it out.

The HVPs from a traditional deck gun will be slower than one launched from a railgun — a little over Mach 3 versus Mach 5 [ed: railgun projectile speed] — but still more than double the speed of an unguided regular shell from the service’s Mk 45 five-inch gun … (1)

Mach 3 = 3344 ft/sec

Wow that’s fast!  Double the speed of a standard round from the Mk45 5” gun!  Wow!  Just Wow!

Just out of curiosity, what is the speed of a round from a 5” gun?  Well, since the HVP is double the speed then the 5” round must be half the HVP, right?  That would put the 5” round at 1672 ft/sec. 

Just for giggles, let’s see what NavWeaps says the 5” round muzzle velocity is.  NavWeaps gives the following data. (2)

5”/62 round types:

Mark 80 HE-PD - 67.6 lbs. (30.7 kg)
Mark 91 Illum-MT - 63.9 lbs. (29.0 kg)
Mark 116 HE-VT - 69.7 lbs. (31.6 kg)
Mark 127 HE-CVT - 68.6 lbs. (31.1 kg)
Mark 156 HE-IR - 69.0 lbs. (31.3 kg)

5”/62 round muzzle velocities:

Mark 80 projectile with Mark 67 cartridge - 2,725 fps (831 mps)
Mark 80 projectile with EX-175 cartridge - 3,450 fps (1,052 mps)
Mark 91 projectile with Mark 67 - 2,750 fps (838 mps)

So, the 5” muzzle velocities range from a low of 2725 ft/sec (Mach 2.4) to 3450 ft/sec (Mach 3.1).  Compare that to the HVP’s speed of 3344 ft/sec (Mach 3).

We see, then, that the slowest 5” round is 81% of the HVP speed.  The HVP isn’t double the speed, it’s only 1.2 times faster which is only 23% faster!

The fastest 5” round is actually faster than the HVP!

What’s going on here?  The HVP is only marginally faster than the slowest 5” round.  Someone at BAE or the Navy is lying confused about their facts.  Does the Navy really not know basic arithmetic?  We’re being fed a lie.  As we noted, the hyper velocity projectile isn’t hyper velocity, at all.  Ignoring that definition inaccuracy, the HVP is barely faster – or actually slower – than a standard 5” round.  Again, we’re being fed a story that doesn’t match reality.

Setting aside the lying confusion, does it really seem plausible that a 23% increase in projectile speed (or slower than a 5” round, depending on the projectile!) will grant all the magical capabilities that BAE and the Navy are claiming? 

Projectile guidance is certainly a useful capability, one would think, although, depending on the guidance process, likely only useful in certain circumstances.  As I vaguely understand it – it hasn’t been publicly discussed in any detail, as far as I’m aware - , the guidance will be a very small millimeter wave (MMW) sensor/seeker.  The inherent drawback to a MMW sensor/seeker packaged in a small 5” projectile is that the power output of the sensor is limited and, thus, the detection range is limited.  This means that the projectile must get close to the target to be able to “see” it.

Presumably, the projectile is unguided until it reaches a calculated near-intercept position and then guides to the target in the terminal phase, assuming it sees a target.  Herein lies the problem. 

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 almost past!  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 the HVP in 1.2 seconds. That's useless for guidance maneuvering. No significant guidance can occur in 1.2 seconds. 

If the HVP round is an air burst round (there is no indication that an air burst HVP is being actively developed but we’ll speculate for sake of discussion) the HVP fuze can electronically react in 1.2 sec but can the round react, detonate, and disperse an effective burst pattern in 1.2 seconds?  I don’t know. 

The critical question, of course, 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.

-Note that the 5” HVP is saboted and, considering the very narrow shape of the HVP projectile, the “average” projectile diameter is decidedly sub-caliber.  Thus, the room available for packaging an electronic power source, radar sensor/seeker, guidance electronics, guidance mechanics, and fins is very limited.  Any radar seeker will be very small and low powered which means very short detection range.  Trying to fit an explosive and fuzing mechanism into such a small package only compounds the problem.

I’m left wondering about the effectiveness of a HVP (that isn’t really hyper velocity and is only marginally faster than a standard 5” round!) in the AAW role.  The speed is actually a potential drawback for a guided and/or air burst HVP because greater speed minimizes reaction/guidance time.  Counterintuitive, I know, but seemingly true.

We see, then, that the entire HVP concept is factually incorrect – it’s not hyper velocity and is only marginally faster than standard 5” rounds – and conceptually questionable.  The HVP round sacrifices a great deal of size and weight to gain, at best, 23% more speed compared to the slowest 5” standard round and is slower than the fastest 5” standard round.  Do the benefits justify this reduction?  I don’t know but I’m dubious.

The one speed related benefit that I could see is that the extreme aerodynamic shape of the HVP might reduce its drag thereby allowing it to retain more of its speed for a longer period of time.  Again, whether that confers an actual performance benefit is questionable.


Reference Data:  Speed of sound ~ 760 mph = 1115 ft/sec = Mach 1


(1)USNI News website, “Updated: Navy Researching Firing Mach 3 Guided Round from Standard Deck Guns”, Sam LaGrone, 1-Jun-2015,

(2)NavWeaps website,


  1. Great points that should kill this program. One more to add. Ship radar fires the projectile where it anticipates the target will be in a few seconds. This only works if no wind exists and the target remains on a perfect steady course for several seconds. But there is always wind in different directions at different altitudes, so the target is always moving slightly and the projectile is pushed around too!

    Therefore, hitting an airborne target more than a mile away will be luck, even if the sensor system works. Even at less than one mile, and incoming missile has a hit to kill target area of less than one square foot! In addition, many anti-ship missiles change course and dive down toward the ship at some point, and missile makers can program missiles to begin a tight spiral flight pattern as they approach a ship to thwart gun launched projectiles, to include CIWS. The Russian Kornet anti-tank missile does this

    The most practical solution is to fire big exploding rockets at incoming missiles. G2mil has a short article about this, calling it NAVROC.

    1. "Therefore, hitting an airborne target more than a mile away will be luck,"

      Which is why a 5" gun with a rate of fire of 15 rds/minute is totally inadequate for AAW. That's why a CIWS has a ROF of 3000-4000 rds/min!

      I just don't see how a slightly faster HVP can transform the ineffective 5" into an effective AAW weapon.

      "The most practical solution is to fire big exploding rockets at incoming missiles."

      You'll recall I posted a battleship story that proposed using 16" air burst shells fired in a cubical pattern. The resulting "box of lead" wouldn't care at all whether a missile was maneuvering! The same concept could be applied to 8" guns though with less sheer impact.

    2. I agree! An 8-inch gun firing 335lb "super heavy" air burst projectiles into the path of a missile will work, and confuse missile guidance systems even if it fails to destroy it. It may include chaff for this reason.

      Critics suggest this will require billions of dollars and decades of yard work to modify our fleet with 8-inch guns. That is true, but not required. We start building several new ships each year. Just start installing 8-inch guns instead of 5-inch guns!

  2. I dont understand the rationale behind trying to turn the 5in into an AAW weapon. It seems that at best itd still be a point defence/last ditch weapon. I understand the cost difference between missles and shells, but is the Captain going to worry about his ships budget when missles are inbound?? Maybe ships should just receive a few more CIWS... Proven systems without millions more spent on R&D for another boondoggle (lie)... And spending money even approaching $100k a round for land attack? Or anti-surface? To deliver a thermos sized round with what? 3lbs of explosive? Seems hardly worth the effort to pull the trigger!! The more i learn about the Navy today, the more I shake my head...

    1. So, a question... Is the HVP somthing the Navy has requested under an "improve my 5 inch gun", or is it somthing BAE has developed and is trying to sell to them or (???)

    2. "I understand the cost difference between missles and shells, but is the Captain going to worry about his ships budget when missles are inbound??"

      The idea was that you could use HVP on targets that don't warrant you firing off expensive missiles, like FACs, Boghammers, chinese UAVs, helicopters, and thereby preserve your missile magazine for the targets that really deserve it.

      And if there are incoming ASCMs, well, it can't hurt to have another weapon in the fight, intercepting incoming missiles.

    3. "The idea was that you could use HVP on targets that don't warrant you firing off expensive missiles,"

      Have you done the arithmetic on the cost? At $100,000 per projectile, a single engagement with any kind of realistic munition expenditure is going to quickly exceed the cost of "expensive missiles". A FAC, Boghammer, helo, or whatever is going to likely require many dozens of rounds unless you assume some ridiculous accuracy. Since every ten rounds equals $1M, the costs quickly escalate and the cost argument is invalid.

      "thereby preserve your missile magazine"

      One can equally make the reverse argument that using a missile preserves the gun magazine. Depending on the ship's intended mission, the gun magazine inventory may be more important.

    4. If the rounds were less expensive this ideal has a certain amount pf logic, particularly the supposed range gain... like all nifty new gun round the price keeps going up. I harpy to see this be a research program. But...

      "FACs, Boghammers, chinese UAVs, helicopters,"

      Would not say bolting on hellfire missiles to all USN ships do those jobs?

    5. @Kath: You're paying more for less range tho, lol. Hellfire has 8km of range in air applications, it's sure sure gonna be less when you fire it from a boat. Plus, it's 114k vs 100k for HVP. then you gotta make the launchers and find somewhere to put them lagi

      ofc Hellfire works right now, while HVP still testing. it took the Navy something like 40 years to get Standard working to the way they wanted.

    6. "A FAC, Boghammer, helo, or whatever is going to likely require many dozens of rounds unless you assume some ridiculous accuracy. Since every ten rounds equals $1M, the costs quickly escalate and the cost argument is invalid."

      A FAC, a Boghammer, and a helicopter are three different types of targets. A FAC is a pretty big boat with many in the 200 to 300 ton range. A Boghammer and a helicopter are much lighter and thinner skinned compared to a FAC.

      If a FAC is within range of your gun, an HVP isn't the right weapon to use. A dozen or so 5-in conventional rounds should suffice for a kill.

      A Boghammer being smaller is a tougher target, but is it worthy of an ESSM or Harpoon? No, it’s not especially when you'll likely fire 2 ESSMs to ensure a kill. It’s worthy of a Hellfire, provided you had one and it was within range. An HPV can reach the horizon (say 12 miles, well outside the range of a Hellfire) in about 18 seconds. Provided the HPV has a decent probability of a hit, it comes down to how many hits result in a kill. Even if it took 2 dozen HPV rounds to kill a Boghammer, which I doubt, it’s the same cost as using 2 ESSMs which are better used against an anti-ship missile.

      The same reasoning above, less using a Harpoon or Hellfire, applies to a helicopter. An HVP might fill the gap between SeaRAM and ESSM and offer another layer of air defense. It comes down the HPV's probability of hitting different targets, how many rounds are required for a kill, and how the cost compares to using other weapons.

      It’s not a wonder weapon, but its worthy of further research.

    7. Apologies all for the last post - urg sometimes you should not type and just go to sleep.

      I think the real issue is I just don't see any realistic testing happening anytime time soon. I really would like the navy to buy a lot more of their missile facsimiles sub and super sonic and start shooting at a lot test ships. The lack of realistic testing makes any claim that any new weapon is better hard to accept. Sure look it did not destroy the gun when fire 20 rounds. But how about the whole magazine? What did they fire at? Or hit? How about some more anti missile tests where nobody knows where the missile is and with some decoys or false targets.

      "It’s not a wonder weapon, but its worthy of further research. "

      I agree but I don't like the way the cost keeps mounting even for the sort of almost HVP. At the current cost nobody will ever fire one before they have try and use it for real.

    8. "realistic testing"

      Quite right. For example, the Navy fired off 20 HVP rounds recently but there is no description of the test circumstances or results. Maybe it was a realistic test (maybe I'll win the lottery!) but probably not. If the Navy wants my taxpaying support, they have to give me enough information to make an informed judgement. Lacking specifics, what I know, at this point, indicates that the benefits of this program do not justify the cost. I'd like to take the Navy at their word but I've repeatedly proven in this blog that that is not a wise course of action!

    9. Admiral Wayne Meyer is credited with the expression, "Build a little, test a little, learn a lot."

      Firing off 20 rounds might have been nothing more than just quick test to prove you could fire such a round from a 5-in gun from an actual warship. If so, this round of testing might have included measuring the overpressure from the round to assess potential damage to nearby equipment, a test of the ammo handling system, and a wear and tear check on the barrel. At least, that's what I would include.

  3. I've read elsewhere that the 5-in HVP round weighs about 40 pounds, so for the same charge it should have a higher muzzle velocity. How much more? Not sure. But, given it has lower drag than a conventional round, it should be able to maintain its speed for a longer distance and achieve a greater range.

    The HVP looks like a scaled down reentry warhead found on an ICBM. So, what is the difference in drag between a 5-in HVP round and conventional 5-in rounds? I haven't looked at in years, but I'll try to find my old Hoerner book on drag.

    1. " should have a higher muzzle velocity. How much more? Not sure."

      The muzzle velocities are given in the post, unless I'm misunderstanding what you're asking about?

    2. The muzzle velocity for the HVP is an estimate based on published reports, which you then compared to data from Navweaps. We don't know with any certaintly the actual muzzle velocity of an HVP round. As we all know, published information isn't always correct.

      As I mentioned earlier, the all-up weight of an HVP round is 40 pounds, about 2/3rds the weight of the rounds mentioned in the post. For the same charge, a lighter round will have a higher muzzle velocity. So, I suspect the HVP has a higher muzzle velocity due to its lighter weight. How much is difficult to quantify without more information.

    3. I have not yet had a chance to personally measure the muzzle velocity of the HVP. Perhaps you have? Until one of us does so, I'll just work with the data that's available, if that's okay with you?

      Along the same lines, I also haven't had a chance to personally verify the 5" muzzle velocities reported in NavWeaps so I guess we should view those with suspicion, also.

      You know, at some point we have to accept some data about something or else there's nothing we can discuss because we can never be 100% sure if we didn't personally witness the events and data. I'll accept published data until I have evidence that it's incorrect and, of course, I'll keep checking and cross-checking everything I can - WHICH IS HOW THIS POST CAME TO BE!! I cross-checked some published statements and found they weren't true.

      If you have better data than that which I'm using, share it. Otherwise, this is the best data available and I'll use it.

      By the way, did you personally weigh that HVP round? If not, I can't accept it because, you know, "published information isn't always correct".

    4. CNOps, there's more merit in Anon's comments and the HVP program than you're crediting, but of course the system as advertised is sorely under-powered. No we can't go measure the muzzle velocity, weigh the projectiles, or test the cartridges in bomb calorimeters. We can discuss the numbers as advertised, but we can also discuss how numbers like these tend to change, just like you frequently point out how prices tend to change. Prices go up, that's just corporations or government bureaucracy - depending on your political leanings. If you fire a sub-caliber round using a modified EX-175 cartridge made to work with the sabot design using as much or more propellant then it will have a higher muzzle velocity than the Mark 80 with EX-175 (Mach 3.1), that's just physics. We can discuss physics, we just have to stay pragmatic.

      Is 10 or even 25 more speed going to make 5" HVP a miracle weapon? I agree, it does not.

      HVP is a whole class of kinetic kill weapons, or at least that's where the research program should be going... because right now it is just a research program. All HVP designs will have very low drag and actuating fins, but potential muzzle velocity varies by gun system and larger HVP projectiles can and likely should be created for 8" or, say, 16" guns.

      5" HVP might be best employed as a minimally guided direct-fire penetrator. The time to impact is improved greatly due to the higher speed and the lower ballistic arc due to the former plus lift, and dispersion is improved by the fins to say nothing of guidance - which is best for a minimally guided round. As CNOps has said, 5" HVP isn't a capital ship sinker, ballistic or cruise missile interceptor, or even a decent gunfire support weapon. It is, however, probably the highest hit probability 5" round versus FABs, and I don't share your doubts about their vulnerability to through-and-through 4" holes - there aren't too many vectors you can draw through a FAB without intersecting something critical. Is that worth fielding? I'm not sure, but it isn't worthless.

      I'd like to hear some ideas for how best to design and employ HVP penetrators for the 8" and 16" guns if somebody want's to pick up on that. Give the railgun discussion a few more years...

    5. "there's more merit in Anon's comments and the HVP program than you're crediting, … we can also discuss how numbers like these tend to change, just like you frequently point out how prices tend to change."

      There's a big difference. Anon was picking and choosing which numbers to believe with no evidence to substantiate the choices. Costs, on the other hand, have been proven with 100% certainty to always go up and, thus, it's completely valid to speculate on cost increases. I have never seen a spec on a muzzle velocity 'go up'. However, if the spec changes then we'll re-evaluate. Until then, lacking any reason to the contrary, I'll stick with the published numbers.

    6. "I'd like to hear some ideas for how best to design and employ HVP penetrators for the 8" and 16" guns"

      I'm not sure exactly where you're looking to go with this?

      The first question that needs to be answered is the penetration characteristics of a high velocity round. Rather than the Navy's public relations demonstrations where they show the impact of a rail gun round on giant steel blocks, I'd like to see a demo of a shot against the quarter inch of sheet metal that passes for a ship's hull and superstructure these days. Would it pass through with no effect other than a small hole, as I suspect, or would it produce some kinetic-thermal effects? Until we know that, there's no point doing any research on anti-ship high velocity rounds.

      I'd also like to see a demo of a high velocity round impacting dirt (like an area bombardment or near miss). Will it bury itself with no effect, as I suspect, or will it produce some kinetic-thermal effect? Again, no point developing rounds until we know that.

      For AAW, can a guided high velocity round even guide effectively? I suspect not. Again, until we know that there's no point developing rounds.

      In short, instead of PR demos, the Navy needs to conduct some meaningful tests.

    7. "the 5-in HVP round weighs about 40 pounds"

      I'm not sure about that. The manufacturer's brochure lists

      Integrated Launch Package = 40 lb
      Flight Body = 28 lb
      Payload = 15 lb

      The relationship between those three and what, exactly, they refer to, is unclear. For example, if the payload is contained within the flight body then the total weight of the flight body is 43 lbs, not 40 and that would be without the sabot launch package. On the other hand, it could mean that the payload comprises 15 lb of the 28 lb flight body which would mean that the empty body shell weighs only 13 lbs. That seems a bit unlikey. It's also not clear to me that the integrated launch package includes the flight body - it sounds like it ought to but it's not unequivocal. It could be that the integrated flight package refers just to the sabot package. If it does not include the flight body then the round would weight 68 lbs or more, depending on where/how the payload fits in.

      Thus, between the HVP reported velocity, NavWeaps reported 5" velocities, and the HVP weight, I find the weight to be the most suspect number!

  4. If the guidance is SEMI-active millimeter radar instead of active that solves the power and range problems, since it will only be a radar receiver, although the ship will need to add a designator radar system to illuminate the target.

    1. Then it wouldnt be an over the horizon weapon anymore. Well at least not that function I suppose.

    2. We don't want to field two different HVPs with semi-active and active seekers for budgetary reasons, and we probably can't stuff both into one package. As CNOps points out, the active millimeter wave seeker is basically useless for fast intercepts and only offers slight gains over GPS/INS-only guidance against fixed and surface targets. A semi-active seeker could greatly improve anti-air performace, but 5" HVP just doesn't have the velocity or lift to match a lot of high speed/maneuverability targets. Larger caliber HVPs with semi-active seekers might be able to engage fighters and supersonic missiles, but 5" HVP is probably limited to helicopters and low flying subsonic UAVs.

  5. From an AAA perspective; 5 inch may be effective against wavetop hugging helos (saturate the general vicinity of a faint radar return with airbursting shells.) or slow flying recon drones (might not have enough radar and thermal signatures for a solid missile lock). But right now that's about it.

  6. Of course as our host says in his post, if the velocity is under mach 4-5 at least, then the HVP is not an HVP just a P. The 120mm M829 has a muzzle velocity of 1,670 meters per second (5,500 ft/s) or Mach 4.7. This round was developed for a 120mm bore weapon in 1993. The HVP, maybe five year old being fired in a gun with a 7mm (pinky sized) difference in bore diameter fails to outperform it. In fact the 5" fires a heavier HE shell than the 120mm so if we made a 5" with a conventional APDS round it should be faster than the main gun of the Abrams and do so for 1/3 the speculated cost of a HVP round you could create a true high-velocity round using proven technology. The Navy could have done this anytime since the 1970's (Sabot rounds were used on 105's by the Israelis in Yom Kippur). But they didn't even during the Reagan years when they pretty much got whatever they wanted. Because they saw no need.

    The argument for a high mach projectile being used in AAW mostly stems from the use of sabot round in both the CIWS and the vulcan on fighter planes. The reduced flight time of the projectiles expands the small window when you have a fast moving target in your cross-hairs and extends the range. But that is also from a weapon firing 100 rounds a second not 20 a minute. A sabot from 5" might be nice for taking out a slow moving drone or helo but a cruise missile not so much.

    1. The media and defense reporting and even BAE use HVP, but the Congressional Research Office uses HVP to refer to the railgun round, and Gun-Launched Guided Projectile (GLGP) to refer to HVP when fired out of 5" gun. Maybe they're on to something with that distinction...

      The designs of M829 and HVP also play a part in the muzzle velocity. While both are saboted rounds, M829 is basically a long dart shape, while HVP is a cone; the former has a lot less drag acting on it. There's also the fact that 5" is a rifled gun, while the Rheinmetall L44 is a smoothbore: smoothbores are more efficient with sabot ammo, because all the energy from the propellant is pushing the round forward, you're not losing energy from engaging the rifling (because, like other sabot rounds fired out of rifled barrels, you're going to need to have bands to engage the rifling on the barrel so that the round can move forward and yet remain still, because fins and spinning don't really mix very well).

      Also, as a point of clarification, 20mm ammo for the M61 Vulcan on US fighters is not sabot, but SAPHEI. It's basically a head full of explosive filler wrapped around a depleted uranium penetrator. Aircraft guns typically don't use sabot because the discarding sabot can potenrially be a FOD ingestion hazard.

      Also I'm starting to think that the idea using a KE HVP round for ASCM defense may be influenced by the Air Force's SACM program and Lockheed Martin's Cuda project, which is basically a small supersonic hit to kill missile. I'm not convinced that's the way to go, but doing the math - assuming HVP is a 40lbs projectile traveling at Mach 3, it has an impact force of 10.5 megajoules. That's going to do a number on most antiship missiles - even if it doesn't destroy the missile outright, you've got a better than even chance of knocking that missile off course.

      But that's IF it hits, which is the big question. On paper, the things that make HVP special - milimeter-wave radar seeker, GPS/INS guidance, steerable fins - are known, mature technologies. The question, which we don't know yet, is whether all those things are coming together into a working package.

      And I dunno, call me old fashioned, but I'd rather use an airburst round to intercept an incoming ASCM.

      Also, some concepts that I have seen talked about for KE HVP talk about using bursting charges to get HVP to fragment into hypervelocity splinters, with the idea being that it'd be artillery shrapnel on steroids, but I think that's somewhat less relevant to the naval context, outside of everyone's sensors and antennas being pretty vulnerable to shrapnel. It's a lot more relevant for the army context, since shrapnel is how you kill troops and vehicles.

    2. I think that in the context of anti missile defense a guided round already exists; dart-strales. It is a 76mm round. Why not just take the existing round, sabot it for use in a 5" gun. It would give it a higher velocity and extend its range.

    3. STALES system requires on mount tracking/guidance radar. DART is a subcaliber round with 8km range and is fired in three round bursts. The radar beam directs the projectile to be close enough to the target to trigger the proximity fuse. Round has less fragmentation/explosive fill but that may not be a problem. YouTube has video of early STRALES or DAVID tests against slow flying drones with intercept occurring at 6.5km, if memory serves me. Italian Navy may not have access to supersonic drones for testing against supersonic ASCMs. I don't know about that. Maybe they have SS drones and maybe not. Such testing would make it a more viable weapon to be usable as a Phalanx replacement as Phalanx is a short range weapon by comparison out to 3km perhaps. Multi feeding option allows selection of 20 different round types from 89 round ready magazine. The 76mm Super Rapid is claimed to have better performance with conventional rounds than the twin 40mm Fast Forty and was selected over it for Italian Navy while improvements have claimed better accuracy than the older 85 rounds/minute weapon which the USN had in service as the Mk 75 which might be why the USN has it's Mk 110 57mm gun which is inaccurate when used with EO fire control instead of radar fire control and suffers from vibration induced inaccuracies if I remember correctly the 2018 DOT and E report.

  7. " just a P"

    I like it! It's a P round.

    "1/3 the speculated cost of a HVP round"

    To be fair, I think the speculated cost of the HVP round is for the guided and/or fuzed round which would push the cost up quite a bit. We've already seen that a conventional 5" round, when guided, gets quite expensive (ERGM and similar).

  8. IMHO; We're trying to turn a Pinto a Mustang by pouring 100 octane into the factory carb and engine.

    1. and supposedly itll have Viper performance, all for a Ferrari price tag. What a deal!!!

  9. A 5 inch gun has similar effects on target as a 105mm howitzer round with a smaller selection of fuses. The 105mm is called a paint chipper for its minimal effects on armor of dug-in troops.
    The Navy needs a bigger gun if it is serious about using the gun to support amphib ops or to battle other ships.

  10. Which is why 8" was called for. When I first read the Zumwalts were going with a 6.1" (155mm), I thought it must be to keep commonality with all of the NATO rounds out there. When I found out otherwise, I was gobsmacked. Were it not for the sources, I'd have figured serious confusion on the part of the writer. Based on rifle ballistics, it's not uncommon for a particular round to start off slower at the muzzle, but keep its velocity extraordinarily well so that at 1000m or 1500m it's the fastest thing out there. I see nothing obvious to indicate that here, though.


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