Saturday, June 18, 2016

Rail Gun Projectile Cost

Wait, what now?  I thought the rail gun was supposed to be able to fire rocks that cost pennies apiece?  Now we’re being told that the rail gun projectiles, filled with tungsten pellets, will cost $25,000 - $50,000 each (1).

One of the selling points of the rail gun was that the projectiles would be much cheaper than any existing munition because the projectile would be an inert lump.  Now, it seems that’s not the case

We’ve already talked about the limitations of a rail gun, chief of which is that it doesn’t explode which makes it useless as an area bombardment weapon.  It’s limited to pinpoint impact on fixed targets.

A second limitation is that the projectiles are unguided although a guidance package is being studied.  Thus, the projectile can’t track moving targets and can’t accept laser guidance.  The targets must be fixed and the co-ordinates known.

Now, we have another limitation and that is munition cost.  At $50,000 per projectile (it’s always the higher cost and you can safely assume that cost will go even higher) we can’t just go flinging these things around.

Could it be that rail guns not quite the miracle we were led to believe?


(1)Wall Street Journal website, “Faster Than a Speeding Bullet - A First Look At America’s Supergun”, Julian Barnes, 30-May-2016,


  1. I'm too lazy to google it right now, but I wonder how the railgun's projected range and cost per round compares to the various guided projectiles compatible with (or adaptable to) standard naval guns: OTO Melara Vulcano, BAE MS-SGP, Raytheon Excalubur, etc. And of course your "old-fashioned" gun doesn't require megawatts of power, and can still shoot cheap unguided projectiles when you run out of magic bullets...

    1. "I'm too lazy to google it right now ..."

      You have to admire a man who's honest! :)

    2. Okay, partially answering my own question, Google indicates that all three systems I mentioned have a per-round cost of around $50k (although it's hard to find a firm figure for any of them). Assuming you could lower that cost through increasing volume, not to mention the savings generated by having a guided projectile that presumably hits the target on the first shot, and the fancy railgun doesn't seem all that economically attractive.

    3. Range bud,
      Rail guns are supposed to be able to drop rounds 100 ml's inland. more than 6 times as far as the guns you mentioned.

    4. "... railgun doesn't seem all that economically attractive."

      More important than economics is combat effectiveness and this is where I question the rail gun. Given the absence of explosive, a one inch miss is a complete miss whereas a one inch miss with an exploding shell is almost as good as a hit. Also, the rail gun is effective only against known, fixed targets.

      The rail gun can be effective but only against a fairly small, niche set of targets.

      So, not only do the economics seem questionable, now, but so too is the general combat usefulness.

    5. CNO, I've read elsewhere that the terminal velocity of rail gun projectile is about Mach 5 (~1,700 m/s). Let's assume it's less than that, say 1400 m/s. That means a 10 kg projectile would hit with 9.8 MJ of energy. If you're off by a few inches or even a few meters, the target is toast.

    6. Walter, i think he means that you miss the target, as in, dont impact on anything in the vicinity of the target. 9.8MJ of energy is significant, but not if the release point is 100 meters behind the target. your proximity fused shell will do the deed no matter how close you come in that 1 meter.

      Im not decrying the rail gun, eventually, in about 50 years, all naval platforms will be carrying them. He's just voicing his concerns about its viability as a weapon.
      And, i simply dont see how they wont be guided rounds. Ranges imply a significant target aspect change by the time the round arrives on target, so there will simply have to be terminal guidance on the long distance rounds. Of course, those in closer proximity, simply unguided that traverses distance in a second or 2 will do the job.

    7. So a couple correction:

      1) Vulcan/Excalibur et al are all well north of 50k per round in reality. Last procurement of Excalibur had a per round cost of ~70k and a total program cost of ~250k per round for reference.

      2) that 25-50k price for a railgun projectile IS GUIDED. Sure we could (and likely will) make unguided solid slugs much cheaper, but the round in actual question is a dispersion guided projectile with a wide area of effect. The projectile uses GPS and/or inertial guidance to reach the target and release/disperse a large percentage of its mass as tungsten pellets. The purpose of this around is to provide area effects, not to hit single hardened targets for which there are separate monolithic guided rounds that should be cheaper. The round in question has in the range of a 25-50 yard kill radius depending on dispersion point.

    8. "If you're off by a few inches or even a few meters, the target is toast."

      We may not be talking about the same miss. I'm talking about a clean miss by an inch. Consider an object placed on the ground and you fire a rifle at it. If the bullet misses by 1 mm, it buries itself a few feet into the ground and absolutely nothing happens to the object because there is no explosive effect. Similarly, if an inert rail gun projectile misses its target by inches, it will bury itself in the ground and nothing will happen to the target. There is no explosive area effect.

    9. Inert rail gun projectiles will be limited in usefulness due to the lack of explosiveness. Even guided projectiles will be limited. The guidance is, apparently, going to be GPS/INS. What's the first thing that will disappear in war? GPS - either via disruption of the GPS signal or disabling of the GPS satellite system. So, the rail gun projectiles will have to depend on INS which is nowhere near accurate enough to hit most targets from a hundred miles.

      Finally, consider the rail gun firing platform - a ship. The ship, and hence the gun, is continually rolling and pitching. Yes, the gun is probably stabilized but it's impossible to stabilize 100%. The tiniest deviation, multiplied by a hundred miles (angular widening), means a miss every time without some form of corrective guidance and I just pointed out the problems with GPS/INS guidance.

      I strongly suspect that rail guns will be far less accurate than we're being led to believe and will be useful only for large, fixed targets like large buildings.

    10. ComNavOps, if GPS is out, every weapon will be less accurate: railgun, chemgun, missile, rocket, etc.

      And chemguns still won't have the range of a railgun, missiles/rockets will still cost significantly more, etc.

      Railguns can and will be equally effective against large targets, area bombardment/suppression, and bunker busting.

      And no, the lack of explosiveness isn't going to make them useless. Cause WTF are you going to use instead? 16" guns that fall 80-90 miles short? 5" guns that fall 80-90 miles short? Missiles that cost 20-40x more per shot? etc.

      BTW, a railgun based HPV round can use star based correction just like ICBMs.

    11. "... the lack of explosiveness isn't going to make them useless."

      Where did I say that?

    12. "ComNavOps, if GPS is out, every weapon will be less accurate: railgun, chemgun, missile, rocket, etc. "


    13. About those "cost estimates" - in the beginning, it's always just marketing. Remember, what happened with a cost of ERGM and LRLAP?

      1) Lockheed Martin was projecting in 2004 that the LRLAP round would have "a cost of 35,000 per round", according to Terry Bowman (LM spokesman):

      2) ComNavOps: "the rounds are reported to cost $35,000 - $50,000 each depending on the source"

      3) FY2017 Procurement of Ammo, Navy & MC - Prior Years (FY 2015):
      0198 / LRLAP 155MM Long Range Land Attack Projectile:

      LRLAP (EX-192) - Guided Projectiles - Unit Cost $476,946.67
      LRLAP (EX-181) - Propelling Charge - Unit Cost $18,353.07

  2. We seem to be underpinning our rapidly decreasing military supremacy on these so called, wonder weapons and systems, while negating increasing proven weapons and technologies capabilities. There is a time and place for R&D, and it isn't the frontline. During WW2, Germany put forth a requirement for a "railgun" to supplement current AA defenses. They design that was submitted, would have required more electrical power then the city of Chicago at the time, per unit.

    Instead of basing future weapons and platforms based on projected capabilities that we hope work, lets continue to develop them, while investing on improving AND maintaining what we have. Once they become mature, then we should incorporate them.

    As regards to shell cost, while 50k-ish is cheaper the a Tomahawk, it is significantly more then the 1940's price of a 16in shell that was around 200.00ish to produce.

    As someone mentioned the short story of "Superiority" in a previous post, I can't help but see the parallels between fiction and reality.

    1. There do seem to be some chilling parallels.

      This may end up being the American equal to the V2 rocket. While it may someday have potential, it's immense costs (and the costs of other high tech weapons like the F-35) may divert funds from other vitally needed areas.

      Training and maintenance have been left as secondary, when in reality they are the most important thing a military has.

  3. "We’ve already talked about the limitations of a rail gun, chief of which is that it doesn’t explode which makes it useless as an area bombardment weapon."

    "Now we’re being told that the rail gun projectiles, filled with tungsten pellets,"

    This is canister shot.
    IE, an area bombardment weapon.

    "A second limitation is that the projectiles are unguided although a guidance package is being studied. Thus, the projectile can’t track moving targets and can’t accept laser guidance. The targets must be fixed and the co-ordinates known."

    Probably, but not necessarily.

    A Rail/Coil *Gun* is the same as a conventional explosives powered *Gun*

    Anything a conventional gun powered by an explosive charge can do, a rail gun powered by an electrical charge can do.

    Theres no particular reason a rail gun cant fire explosive shells, so far, the assumption has been that solid shot would be more than enough destructive force
    No reason we wont see the whole gamut of projectiles, and some new ones.

    Gun launched drones are much more viable if the "gun" can be better controlled

    Rail Guns are to chemical guns as EMALS is to steam catapults
    And yes, currently none viable should top that list...

    1. EMALS and steam catapults launch aicraft at the same speed. But, rail guns because of the significantly higher muzzle velocities, put far more stress and acceleration loads on the projectile compared to chemical guns.

    2. This comment has been removed by the author.

    3. Theres no *need* for a railgun to have higher muzzle velocity.
      They can do, but theres no reason you cant dial them back and throw conventional shells, although fuzing might be an issue.

    4. TrT, you reduce the muzzle velocity, you absolutely kill the Rail Gun's range, meaning that expensive magic bullet projectile is only going to be traveling about as far as a conventional projectile.
      That's how the Rail Guns get their range. The sheer speed of the projectile.

      So, yes, there is a very huge *need* for a railgun to have higher muzzle velocity, as far as that railgun and its designers are concerned. Its only reason to exist!

      - Ray D.

    5. The whole idea behind a rail gun is to hurl projectiles 200+ miles down range, which requires a muzzle velocity on the order of 8,000 feet/second.

      But, I guess you could dial down a rail gun to fire a conventional round. But, the round would have to be encased in a sabot which probably limits the size of round you could fire.

    6. "This is canister shot.
      IE, an area bombardment weapon."

      No, or at least not in the sense I'm calling area bombardment. I'm referring to high explosives carving out giant craters across the landscape - like WWII 16" battleship shells providing area bombardment.

      A small fragmentation round like this rail gun projectile will have almost no area effect in the sense I just described. It would be effective against personnel in the open but not much more. Perhaps I'm underestimating the effect but I'll need to see proof before I call a rail gun projectile an area munition.

    7. A 10-20g tungsten pellet traveling at mach 5 will do much more than just be effective against personnel in the open. That will punch clean through anything short of a tank. Each of those pellets has a kinetic energy somewhere between 1-2x a .50 bmg round with roughly 2x the velocity. Anything a .50 BMG AP/API round can punch through, those pellets are going to swiss cheese. The armor defeat capability of those pellets is a lot closer to a 20-25mm AP round in reality(due to density and velocity being the primary factors in armor defeat hence things like APFDS). So you are talking on the order of 2-4 inches of RHA of penetrating power.

      And you are looking at around 1000-3000 pellets per dispersion projectile.

    8. They couldn't be round, they would bounce or shatter on impact. That would require flechette style submunitions, which would decrease the number carried, which in turn decrease the area of coverage thus effectiveness. Additionally the 25mm sabo rounds dose not have penetration to deal with tanks reliably, hence why the M2 platform has missiles.

    9. In addition to that, that listed 8500ish fps speed is only at launch. I guesstimate around 3-4k fps at impact, which would mean around 2-3k fps speed for the submunitions, dependent on shape and time of release. A better chose would be some sort of dispersed guided, explosive form projectile, similar to the hornet mine.

    10. Andrew S., a round Tungsten pellet traveling at mach 5 isn't going to bound when it hits something like steel, unless you think golf balls traveling at 90+ MPH bounce off glass windows... And they wouldn't use flechette style sub-munitions, they would use either cubic or ball based sub-munitions. For maximum volume efficiency, cubic would be the way to go, but that's much more complicated to pack and produce.

      And no one is planning to use dispersion rounds to deal with tanks, but they'll take care of everything up to full blown tanks. Basically anything that doesn't have more than ~100mm of RHA topside will be swiss cheesed.

      I'm using 1715 m/s as that is Mach 5 and is the estimated terminal impact velocity for the 32MJ railgun at ~110 nmi. Sub munitions have the same velocity as the projectile as they are released in flight at a determined distance from target (based on required dispersion characteristics).

      And at the velocities we're doing with and the projectile weights, an explosive fill would be basically pointless. If Tungsten pellets at Mach 5 aren't going to kill something, a small explosive isn't going to do it either.

    11. I was meaning something like the m2 SLAM or Grumman's "brilliant anti-tank" submunitions. They work by detonating a small explosively formed penetrater (EFP) that attacks top down. EFP's penetration values are quite high, cant be intercepted, and largely negate ERA found on most tanks. But realistically, your quite right, the amount that could be carried wouldn't be worthwhile.

    12. Eh? Part of the whole point of ERA is to break up a penetrator and ERA works equally as well if not better on EFPs than APFDS. There is a reason that every modern HEAT weapon has a tandem configuration: because single EFP HEATs are easily defeated by ERA.

      The force of the ERA causes the EFP which is quite fragile being effectively liquid medal to deform and become ineffective.

    13. EFPs negate ERA due to standoff, ie where it was detonated, and the misznay-shardin effect. An EFP creates a molten copper slug that requires standoff to properly form, at which time it strikes the target at around 2k m/s. ERA just cant detonate fast enough to disrupt it, compared to HEAT charges that activates ERA while its still forming the jet. The report I have link below, has further in information.

  4. As regards to canister shot, the amount of submunitions that can be be carried are dependent on the size of the carrier projectiles, which I believe are currently smaller then 155mm. Not to mention, the complexity of such a round is greater the a pure point initiated, base detonated HE round, compared to the airburst mode required, further reduces the number of submunitions or range performances of the "railgun" round.

    As the Iranians, Russians, and even Afghanistan insurgents have proven, anything remote controlled, wirelessly can be spoofed. I would discount any meaningful effect drones and drone munitions would or could have, upon the battlefield.

    1. Smaller than the 155mm shell in physical size, but, due to the enormous kinetic energy associated with the pellets, you can pack a lot of smaller pellets into that space, knowing that coupled with 6000 kmh impact velocity, you dont need a very big weight to make a very big boom.

      Wait for the infantry rifle variant, its likely about 30 years away, but, you'll be accelerating thousands of needles per second at your target, each one weighing a few grams, yet travelling at a few thousand kph, only a tiny burst would be needed to finish even the hardiest of targets... In theory

    2. Nate, again, you do sarcasm well. But I'll run with it. With no theoretical decrease in range, for the g's pulled, you would a significant amount of the mass of the projectile, I guesstimate between 25-40%, for the necessary timing & release systems. That leaves around 15-25% for casing the submunitions, so best case secenario 60% room for these ball bearings, neglecting any guidance capabilities. With some quick googling the most common size ball bearing is 10mm at 4.5 grams each. Times that by 8500ish fps, you get around 85-ish joules or 63ish psi of each projectile on impact, barring drag of course. Lethal on troops in the open, but thats really it. That's around 4.2lbs of submunitions for a 7lb projectile.
      Also, increasing dispersion decreases hit probability.

    3. Why does a rail gun canister shot have to work differently than an explosive canister shot?

      Whats different besides the initial blasting charge.

    4. Realease mechanism has to be more robust and accurate in order to survive launch and achieve the desired spread.

      It might need a blasting charge, but most submunitions dispenser use imparted gyroscopitic effect to spread bomblets / canister.

    5. Um Andrew S, you math is off. for a 4.5g projectile at 1715 m/s, you are looking at 6.6 KJ. KE = .5M*V^2

      Also for reference,a 10mm tungsten BB weighs ~10.1g.

      Also for reference, a 10mm tungsten BB will punch clean through inches of RHA at 1715 m/s. It has a KE of 14.85 KJ in range with a .50 BMG AP/API with an energy density 3-4x higher. Its energy density is closer to that of 20-25mm APFDS rounds.

    6. I figured my math was slightyly off, but not that far off. Could you post the entirely of the equation for me?

    7. Ok, figured out where I messed up, my conversions.

      Ek=1/2×0.015kg×(2590)^2=50310.75j or 50.31kj.

      Btw, where are you getting that 1715m/s from?

    8. 1715 m/s is Mach 5 at sea level which is the approximate terminal velocity at max range for the HVP fired from a 32MJ railgun as per the specifications.

    9. thx ats,
      Andrew's assertions that the round would deliver the punch effectiveness of a bitch slap by a 12 year old girl didn't add up, but my math aint all that.

    10. So, what are you people claiming about hitting power? Depending on the specific numbers, you seem to be calculating kinetic energies of 6-15KJ or thereabouts.

      For comparison, a 16" battleship AP shell 2700 lbs (1225 kg) has an impact velocity of around 500 m/s at long range, according to Navweaps. If I did the math correctly (someone check me), that gives an impact kinetic energy of 153MJ.

      I have no feel for translating kinetic energy to impact damage and effects but 10KJ is only 0.01% of a battleship shell. Are you sure that 10KJ is effective?

      The specific claim that a 10mm beebee will punch through inches of RHA at speed seems suspect. Do you have a reference for that claim?

    11. Those are kinetic energies for the individual tungsten pellets. Full weight kinetic energy for a solid round at max range would be: ~37 MJ assuming 25kg weight and mach 5 terminal velocity.

      Once again, 10-20 KJ is per tungsten pellet which is on part with a .50 BMG API bullet and there are on the order of 1000s of them per dispersion shell.

      It isn't a 10mm bb. It is a 10mm TUNGSTEN BB traveling at Mach 5. It has higher velocity than a .50 BMG SLAP round at the muzzle and higher KE. At point blank, .50 BMG SLAP will penetrate ~2" of RHA.

    12. So, we're getting all excited about being able to deliver the equivalent of a machine gun burst using a rail gun?

      Also, where do you get 1000s of pellets per shell? Given the size of the missile, that seems unlikely. Do you have a reference?

    13. Um, its a bit more than a machine gun burst. It is also 100+nm away.

      As far as 1000s of pellets per shell, that basically the volumetric of it. We're talking fairly small likely 5-10mm pellets/cube, the packing should work. The projectile is on the order of .5m or so. The vast majority of the volume of the projectile can be used to pellets.

    14. "Andrew's assertions that the round would deliver the punch effectiveness of a bitch slap of a 12 year girl..."

      And thats the reason henceforth I shall never do math again, in public discussion. Thx Nate :)

    15. > ~37 MJ assuming 25kg weight

      Actually, the HVP weight is more likely to be around 25lb, not kg — at least, according to the BAE site:

      HVP Weight:
      Integrated Launch Package 40 lbs
      Flight Body ..............28 lbs
      Payload ..................15 lbs

    16. Yep, 28Lbs instead of 25KG. Cuts the KE in roughly half.

    17. "As far as 1000s of pellets per shell, that basically the volumetric of it."

      The projectile is 25 lb (not kg) which is 11,350 g. If each pellet is 20 g, simple math gives a pellet number of 567, not thousands. Now, that assumes that the entire projectile is pellets and it's not. The casing, nose, fuzing/explosive, electronics, etc make up some of the weight and volume. Let's say that half of the weight is those things. That drops the pellet number to around 280.

      If we'er truly talking about spherical pellets, then there's a lot of void space in the packing. Let's say 20% void. That reduces the pellet count to around 227.

    18. So, it appears we're talking about 200 pellets with the kinetic energy of a machine gun round or less (some of the energy will be lost due to the bursting, presumably). That has some use, especially when delivered 70 miles downrange, but it's hardly the devastating weapon that many people seem to envision.

    19. It might be roughly equal to the bursting warhead of the BTERM for Mk-45, which consists of ~10 lbs tungsten fragments dispersed by explosion of 7.6 lbs (3.4 kg) HE charge:

    20. CNO, I think you are greatly underselling the effects. First, we're probably looking at 10g pellets not 20g. Weight wise you are looking at like 3/4 total weight being pellets.

      The actual effect is closer to a multi-second gun run with say a 20mm or 25mm Gatling gun( aka emptying the entire ammo box). AKA, some serious hurt with anything short of multiple inches of RHA or feet of concrete not affecting the outcome.

    21. ats, be careful not to fall into the habit of making unsubstantiated claims!

      You say 10 g pellets. Do you have any reference to support that? And, if you are correct, that would increase the number but cut the kinetic energy in half which probably makes the overall impact less effective.

      "Weight wise you are looking at like 3/4 total weight being pellets."

      Again, do you have any reference to support that? I've given my logic based reasoning for the numbers I calculated. Simply picking an alternate weight out of the air is not credible. Give us something to work with or I have to stick with my calculation.

      Finally, delivering a munition that approximates the effect of a machine gun burst is not very effective. For starters, it's only effective against exposed personnel or very thin-skinned vehicles. Hitting those kinds of targets a hundred miles in the rear of fighting is probably not all that useful and certainly doesn't justify the enormous expenditure of the rail gun system! Also, those kinds of targets are generally moving targets which the rail gun can't engage. This is looking to be a very limited weapon - effective against known, fixed targets but little else.

      As far as underselling the effects, I'm using math and science to estimate effects. I'm not "selling" anything. The results are what they are. If my math is wrong or we're using inappropriate formulae, then correct us. Simply saying "underselling" without any supporting data or calculations is just hand-waving.

      I'm not a rail gun or explosives effect expert. I'm completely open to a better way of calculating this stuff or to using more precise data but I'm not open to unsupported generic statements like "underselling". If you think I am, then prove it and I'll happily change my opinion.

      Good luck. I hope you do find additional data. I'd like to have a better idea of what the real effect of the rail gun projectile will be. Let me know if you find anything.

  5. When assessing the rail gun's cost per round and whether guided rounds improve the rail gun's economic viability, we should also consider the cost of the barrel in addition to the cost of the ammunition. The WSJ article said that the barrel will be usable for 1000 shots. I bet these barrels are expensive - maybe $50,0000,000 a piece. At that barrel price and a 1000 shot life span, the depreciation on the barrel would add $50,000 of cost every time the weapon is fired. In other words, even if the projectile isn't guided it will still be expensive. It seems to me if that if the barrel is adding tens of thousands of dollars to the cost of each round, then it could make sense for the rounds to be guided. The ratios of the guided vs unguided accuracies and the barrel cost vs added cost of the guidance system will determine whether the guided rounds will reduce the expected cost of hitting the target. These numbers are not available so I can't do the expected value calculations to give you the final answer. Also, I do not know if the capacitors have to be replaced or if they are durable.

    The WSJ article did suggest that the Navy has a developed guidance system using cell phone technology. Based on the reference to "cell phone technology" I am guessing that the guided round either (1) uses inertial guidance from an accelerometer and a data input of the ship's position at the time the round was fired or (2) GPS guidance.

    In addition, the rail gun's speed is so great that a guided canister round might be useful against enemy ships. The article said that the round's initial velocity is 4,500 miles per hour. Air resistance will slow the round, but we are probably talking about hitting a target 100 miles away in 2 minutes. A ship moving at 30 knots will travel a little more than a mile in 2 minutes. Therefore, the Navy would then need a terminal guidance system that could detect a ship within a couple mile radius of the ship's last known position and maneuver the fast moving projectile close enough for the canister to hit. These are ballpark numbers that give us an idea of the scale of the challenge for hitting a moving ship while utilizing the rail gun's long range.

    Another unknown is that I simply do not understand what a solid rail gun round or a canister round will do in terms of target destruction. It seems like the round would go straight through the ship and cause only a narrow path of damage. On the other hand, solid shot bounced around creating devastating shrapnel.

    However, a rail gun round's kinetic energy would almost certainly mission kill a missile. The rail gun round would be useful for intercepting ballistic missiles but could fail against a cruise missile that could detect and evade the rail gun round (however, detecting the rail gun round might require cruise missiles to use radar - in effect broadcasting their attacks).


    1. KS,
      I think you'll find unguided is a thing of the past in western forces, where we're now even trying to figure out ways of guiding rifle bullets.

      In gulf war 1, 3% of the munitions expended were guided munitions, yet they caused over 75% of total damage.
      It doesnt matter the cost per round, or even cost per damage inflicted, its the effectiveness of mission parameters. War will always be expensive, idea is to finish it as quickly as possible, and these days, with as little collateral damage as possible. Hence, guided rounds.

    2. KS, for an unhardened target like a ship, the canister round will be like being hit with 1000+ 20-25mm AP/API rounds in an instant.

      A solid round against an unhardened target like a DDG/CG would go completely through the ship leaving pyrophoric effects behind. It would hurt but not super bad. Solid rounds work much better against hardened targets like heavy armor and bunkers.

    3. Please keep in mind that we are talking about taking out a naval vessel that probably cost a billion or more dollars to build and then taking it out with a 50 thousand dollar dart. I call that one hell of a bargain.

  6. Dumb question - if the tungsten is so expensive, why not fill the projectile with something else? I know Tungsten is the densest but even at half the density (say lead), that should still give a much better range and velocity than a normal 5". Maybe just keep a small number of Tungsten rounds for key situations. Or is there another technical reason why it needs to be Tungsten?

    1. The issue is you are mostly volume limited and you want to have AP effects. Lead is just too soft to have any AP effects even against most body armor let alone something like an APC. Tungsten isn't used just because of its density but also because of its hardness. There are very few other materials out there with the same level of density and hardness. Hardened steel has close to the same level of hardness but almost 1/3 the density. Most materials with the same level of density tend to be very soft such as lead.

      Hence, if you want to be able to penetrate things tungsten is the material choice.

  7. Tungsten can survive the heat generated at launch and is most likely affected by magnetics to work. My guesses.

    1. There is minimal heat generated in the actual projectile. The heat is pretty much localized to the rail mating interface (friction) and to the localized high flux region (electrical resistance/magnetic induction heating).

      The actual projectile can be completely non-magnetic and the gun will function completely fine. The magnetic propulsion is acting only upon the sabot. In fact, the fields are so localized that the observed magnetic flux at the tip of the actual projectile are almost zero.

      There was a good presentation from one of the gov weapons groups dealing with triggers, guidance, and environmental factors related to those but I can't find it for the life of me. The net take away though was that at least for the guidance/nose electronics, the environmentals are no worse than any other gun and in some respects (Max G) better. Max G actually tends to be significantly lower for rail guns than chemical guns because of the constant acceleration instead of the peak down acceleration.

    2. There may be minimal heat generated in the projectile during the launch cycle (and I'm by no means sure that is true) but there must be significant heat generated on/in the projectile during flight from atmospheric friction. Whether it's enough to cause problems with any internal electronics, I have no idea.

    3. CNO, the HPV railgun projectile actually spends a minimal amount of time in atmosphere. The primary heating point should actually be atmospheric re-entry.

      As far as heat for the launch cycle, yes, the actual projectile is extremely minimal heating effects during launch. As I said, all the frictional heating is on the sabot as well as the resistive and flux heating.

      Regardless, heating effects though any phase of the projectile's live are not dissimilar to those experienced by any other gun based projectile.

    4. I have not read that projectiles will be exo-atmospheric. Do you have any reference supporting that?

    5. I suspect you're grossly underestimating heat effects. Do you have any data showing heat effects on a projectile or are you just speculating, like me?

    6. ONR slides indicating that max apogee of 150KM(500k ft) which qualifies for space. Granted it isn't "strictly" exo-atmospheric in the scientific sense(exosphere goes out to ~10k KM), but pretty much everyone counts that once you are in the thermoshpere that you are in effect exo-atmospheric.

      As far as heat effect, it what I remember from that slide set on triggers/sensors/etc for HVP that I can't seem to find atm.

    7. I'm guessing that you're describing the case of a hundred+ mile shot. Obviously, a 1 mile shot wouldn't go straight up 500,000 ft and then straight back down. Presumably, the apogee rises with each mile of range and may, at some range, presumably the max 100+ mile range, reach 500,000 ft. Thus, for every shot less than 100 miles the apogee is less and the "time in atmosphere" is greater. Does this sound reasonable?

      Regarding heat, I'll repeat, I have no idea what the magnitude of frictional heat buildup is but I suspect it's significant (immense). Everything (meteor, aircraft, re-entering spaceship, bullet, U-2 spyplane, etc.) that moves at high speed in the atmosphere experiences significant heat buildup. There is no reason to think a rail gun projectile will not also experience significant heat buildup. Whether it will rise to the point of affecting electronics, I have no idea.

      To the best of my knowledge, no rail gun projectile has been tested at long enough range to reach a 500,000 ft apogee. To the best of my knowledge, no rail gun projectile has been tested for heat buildup during flight.

  8. A couple of clear up points

    A rail gun is a GUN, that uses electromagnetic rails (or coils) to propel a shell, instead of a chemical explosive.
    Thats it.
    Thats all thats different.

    A conventional gun uses a chemical explosive to propel the shell, a rail gun uses an electro magnetic field.

    Railguns, because they arent limited to a single cataclysmic blast, can, in theory, propel shells MUCH MUCH faster than chemical guns, but they dont need to.

    As a standard gun has a selection of propellant charges, a railgun can be operated at a far greater number of power levels.

    A railgun could fire a "standard" 155mm shell at standard velocities, re-engineered to be propelled that way, remove the propellant charge from the base, add a propellant block in the base that a field propells, or some sort of sabot that wraps the shell and is propelled, or just propel the iron in the shell. Probably tinker with the fuse to make sure it can survive the field.

    However, a rail gun can, because it isnt limited to a single short chemical explosive burst to propel the shell, fire a shell MUCH MUCH faster than a conventional gun.
    So fast, that a solid shot, would be more than enough to kill a tank. Im four beers deep so cant remember how conservation of momentum works, but if we use the less accurate conservation of energy, a 20kg shell moving at 1,000m/s impacting a 40,000kg tank would propel it at 0.5m/s, which doesnt sound a lot, until you multiply it by 60 seconds in a minute, and 60 minutes in an hour, and get 1,800 kmh.
    The reality is the solid shot at those velocities would just punch a hole and keep going.

  9. Does that mean you could use a less dense filling but it would just have less range and/or less velocity on impact as i asked earlier? It might not be as good as Tungsten, but it might be enough to do more damage at more range than a standard 5"?

    1. "Does that mean you could use a less dense filling but it would just have less range and/or less velocity on impact as i asked earlier? It might not be as good as Tungsten, but it might be enough to do more damage at more range than a standard 5"?"

      Pretty much, in war, we rarely use the best, in peace, its all we use.
      RDX is 50% more powerful than TNT, and despite being developed in 1899, was still used only in Torpedos and Earthquake bombs, throughout the second world war.

      You could fire a tenis ball at those velocities and do damage

  10. Barring major technological advances, this could end up being the American equal to the Paris Gun.

    I would like to know the barrel life of this weapon and the total systems cost. Also, factor in that the operator will likely have to change the barrel frequently due to wear.

    While it is long-ranged and there is no way to stop a rail gun projectile, it may prove expense and impractical, at least until we see major technological advances.

    It would be interesting to see how accurate the weapon really is. High muzzle velocity may actually hurt the gun in this regard.

    1. It really does not have what you would call a barrel.
      It has two bolted down rails that dead short across the projectile causing the expulsion of the offending object to the current.

    2. The current barrel life is limited to a series of shots. However, the advances are already well underway and they envision extending the life to thousands of shots shortly.

    3. "they envision extending the life to thousands of shots shortly."

      They - whoever they are - envisioned the F-35 in squadron service about a decade ago but they were wrong. They envisioned the LCS being a miracle ship but they were wrong. They envisioned the Ford costing around $8B but they were off by $4B-$5B or so. They envisioned the Zumwalt providing affordable gun support with LRLAP munitions but they were wrong. They ... well, I think you get the idea.

      They can envision anything they like. The reality is always quite a bit different.

      Rather than make a trite claim that is demonstrably wrong, why don't you do a bit of research and then update us on challenges associated with getting longer "barrel" life out of a rail gun. What are the main problems? What approaches are being taken to solve the problem? How likely are the solutions to work? What will they cost? Will the solutions hold up in combat? Can the "barrel" be changed at sea? How quickly?

      You clearly have some degree of interest in this so give us a useful, informative comment! I look forward to learning something about this!

  11. I wonder what the potential is to cause a vessel to expend it's AA ordnance by firing with less velocity but more rapid fire ie bung rocks at it until it runs out of ammo - they'd have to be pitched for them to have to fire to avoid damage.

    1. I'm not sure as to the mechanics of "shooting down" a solid shot at supersonic velocity, well, I am, I'm sure its impossible.

      Missiles are "intercepted" primarily by destroying the control surfaces which cause the missile to maneuver itself off course. The alternative is they explode the warhead.
      Artillery are the same, a small impact can knock a shell off course, or disable or detonate the warhead.

      A missile is essentially convinced to missed, a shell is moving slowly so can be nudged off course.

      A Solid Shot doesnt have control surfaces that be impacted causing its own propulsion to force it off course, nor does it have the slow speed of a shell to give time to push it off course.

      Imagine, its heading side on against a Burke, dead centre. Its 1000metres out, travelling at 1000mps, you need to move it 80m to cause a miss, in a second.
      You would need to accelerate it at 180mpsps, 19g, sideways, or up or down I suppose by a smaller degree, but, no. Just no

    2. TrT,
      wouldn't inducing tumble in the solid round have enough effect to alter its course sufficiently?
      Perhaps not at 1000m out, but at sufficient range, tumble should cause a miss?
      Unless I'm missing the point that at these hyper velocities, the interception alone couldn't be generated at any kind of distance,
      time of detection + time to generate intercept calculation + time to launch counter shot + distance to target = projectile has already passed through target?

  12. Regarding High Atmospheric Shots

    These will either be inaccurate, or as accurate as IRVs and as expensive as IRVs

    If there was a cheap way of accurately dropping stuff from orbit, we'd be using it to drop nukes.

    1. pretty sure there is some rule we signed onto that prohibits us from "dropping stuff from orbit." If we could do this, it would actually be pretty cheap to store a bunch of nukes up their in a "cloud" ready to go.

    2. Um, high atmospheric shots are no more inaccurate than any other shot these days. CEP of IRVs are in the low double digits without GPS.

      Lets put it this way, have you watched any of SpaceX's rocket recoveries? Cause all of those have had a CEP of like 1-2 meters.

    3. Yeah, and they arent cheap.

    4. its not nukes that we're worried about as space based weapons, ICBM's have strike times in the minutes, which is low enough as is i think,
      Its 50cm tungsten rods, with a tiny seeker head, dropping down and annihilating tank divisions which generated the prohibition on space based weapons. And yes, they'd be cheap as chips, getting them in place, that would be expensive, but manufacturing them, very little.

      Having said that, other uses for rail guns, eventually, will be to launch micro satellites, if we could figure out how to make such devices that can survive the initial 500G launch acceleration.

    5. Escape velocity is 12,000 metres per second, theres simply no object that can travel that speed at low altitude.
      Maybe if you built one in a tall mountain, even then you would likely just be replacing the first stage of a rocket, or chucking lumps of metal up in to orbit.

  13. Aren't Cheap? you talking about SpaceX's rockets or IRV. As far as SpaceX, the technology they are using is pretty damn cheap. Its not like it takes a lot of hardware to do the calculation. Same for the IRVs. The cellphone you threw out 5 years ago has more than enough hardware to do it.

    And the IMU technology on IRVs can be had for pennies on the dollars these days and is more accurate to as well. Technology marches every onward and upward.

    1. I'm not sure how to explain that SpaceX rockets arent economically viable if you strap a bomb on them and drop them on Technicals

  14. Interesting article I just found, discussing just using the railgun round to boast the capabilities of existing, conventional guns, among other things.

    1. This has been POR for quite some time. The HVP projectile has be fired from a wide variety of weapons though generally with reduced effect.

  15. Never understood why they are concentrating on long range gunnery with the railgun. Seems to me the principal would be much more useful for close-in salvo defence.

  16. I'm sorry to say gentlemen but you are all thinking backwards in terms of what this projectile will do when it goes through a ship traveling at mach 6 or 7 it foot lbs of energy would be more than the weight of the entire ship,, about 30994957 lbs of energy.
    When firing at a target from horizon to horizon at a ship, there will be no such thing as a miss, and the most vital functions of that ship would be disabled by this man made meteor. When this dart hits its target it will be traveling faster than any other ship munition in existence leaving the barrel. even 100 thousand dollars for a guided round is way cheaper than a cruise missile that cost up to a million dollars.

    1. What happens when you shoot a rifle at a piece of paper? Is the paper destroyed? No. The bullet passes cleanly through leaving only a tiny hole. Can you see the analogy?

  17. When computing kilo and megajoules, bear in mind that when your lover touches you with her hand, that is a force and that is one situation, and when the doctor applies the same force but at the end of a hypodermic needle, the situation changes.

  18. The rounds fired from the U.A. Army's Paladin self-propelled howitzer already cost over $68,000 a piece, so this is still cheaper and for greater capability. It's true that a railgun round won't detonate, but for wide area of effect it doesn't have to. If there are volatiles at the target those will go up from the sheer force of impact, and the kinetic energy imparted to the ground, structure, or vehicle will be a lot like an explosion.


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