30mm Better Than 57mm?

The MK46 Mod 1 weapon system fires a round during a live-fire qualification exercise aboard the amphibious transport dock ship USS New Orleans (LPD-18). US NAvy Photo

The MK46 Mod 1 weapon system fires a round during a live-fire qualification exercise aboard the amphibious transport dock ship USS New Orleans (LPD-18). US NAvy Photo

The Navy has apparently made a decision I find incomprehensible. They have decided to alter the DDG-1000 design, replacing the two 57mm Mk110 mounts (the same gun on the Bertholf class and projected for the OPC) with two 30mm Mk 46.

According to the US Naval Institute News,

“The Navy has replaced two 57mm guns planned on the Zumwalt-class guided missile destroyer designed to fight off swarm boat attacks with a smaller pair of 30mm guns, Naval Sea Systems Command (NAVSEA) told USNI News on Monday.”

and later,

“A follow on 2012 assessment using the latest gun and munition effectiveness information, concluded that the MK46 was more effective than the MK110 CIGS. Based on that assessment, approval was received to change from the MK 110 CIGS to the MK 46 Gun System. In addition to the increased capability, the change from MK110 to MK46 resulted in reduction in weight and significant cost avoidance, while still meeting requirements. DDG 1000 is planned to have two medium range MK46, 30mm Close-in Gun Systems that will provide a robust rapid fire capability and increased lethality against hostile surface targets approaching the ship.”

The Mk 46 mount uses the Mk44 30mm chain gun that is derived from the same 25mm chain gun used in the Mk38 mounts. It looks like a small tank turret, but I understand it is not armored. It can be remotely controlled or manned by an on mount operator.

Comparing the two weapons,

Range of the 57mm is four or five times the range of the 30mm.
Projectile weight of the 57mm is about six times that of the 30mm.
Rate of fire is similar, 220 for the 57mm and 200 to 250 for the 30mm.

The only advantage I see for the 30mm is that it has more ready ammunition on the mount (not sure how much but apparently at least twice the number of rounds meaning it should be able to fire twice as long without reloading).

46 thoughts on “30mm Better Than 57mm?

  1. I was surprised the rate of fire was not noticeably better than the 57, I was expecting that to be the big deal maker…yes it can fire continuously for a longer amount of time, but I’m curious if it has the same warhead options as the 57 has (burst mode, impact, timed, etc.)

    • Yes, larger projectiles almost always have smarter fuses, but even if the fuses were the same, say using an air burst to hit a boat with fragments, the 57mm would have a much larger kill radius.

  2. Range doesn’t really matter, such speedboats can fire a devastating salvo with makeshift 70 mm MRLs from outside effective 57 mm range.
    The effect is likely comparable as well, if the target is indeed a speedboat.

    A noticeable difference may be in metacentric height (a known problem of the class).

    • I think range does matter, the prototypical swarm boat is equipped with multiple unguided 107mm rockets. Specs are here: http://www.armyrecognition.com/china_chinese_army_artillery_vehicles_systems_uk/type_63_107_mm_multiple_rocket_launcher_system_data_sheet_specifications_information_description_uk.html
      These have a range of 8.5 km but are very inaccurate at that range against a moving target. They will almost certainly try to get closer before launching. Its entire range is well within the range of the 57mm but it outranges the 30mm.
      Really I am more concerned about boats carrying torpedoes and cruise missiles. There is a good chance torpedoes would be launched in the area between the max range of the 30mm and that of the 57mm and if a saturation cruise missile attack is attempted the ship may need the additional AAW capability of the 57mm.

      • I wouldn’t think of cruise missiles in this context; think of the potential of Shrike missiles. Its hard to knock out an entire AESA antenna, but a couple missile warhead impacts at Mach 3 aren’t anywhere near harmless.

        By the way; I wrote “effective 57 mm range” for a reason; the max range isn’t what matters.

        Finally, let’s remember this speedboat obsession is ridiculous anyway. A fishing vessel or small ferry is a much better Q-boat to move within range to the target. A low tech threat ‘discovered’ by the USN itself back in 2002 which sparked a decade of countermeasures hysteria won’t be a credible threat in 2016.

      • I also feel that the swarm threat is overblown, and in any case not much of a concern for the Coast Guard unless our units are sent to the Persian Gulf to screen tankers as was talked about during the “Tanker Wars.”

        Basically if you can defend against aircraft, defending against boats that are one tenth the speed should be relatively easy.

        The Iranians are likely to use the swarm as a distraction from their more destructive threats, but if they are to launch 107mm rockets with any degree of accuracy, they will have to come inside the 57mm’s effective range.

        In addition to the unguided rocket equipped boats, the Iranians have a large number of boats equipped with anti-ship cruise missiles and many semi-submersible torpedo boats. Most of these will have to see their target before launch, but they all outrange the 30mm.

      • I had multiple 107mms fired at me at FB Tagab in early 2007. The closest one came was about 100 meters from our base. That’s out of probably 10 or so launched at a stationary target the size of a WalMart parking lot.

  3. In any case I don’t want to see the 30mm substituted for the 57mm on the OPCs (unless they also added at least Hellfire or something similar) because the max range of the 30mm would put the cutter within range of all sorts of potential improvised weaponry that might be added to a vessel.

  4. Incredibly stupid in terms of effectiveness, but reading between the lines, I think SO hit the correct point: there’s a weight issue, and the 30s are lighter.

  5. Since the DDG-1000 class is truncated to only 3 ships, this, by itself, isn’t a huge impact on the Mk.110 program, but with the truncating of the LCS as well, this article begs another question: how sustainable is the Mk. 110 gun program?

    Originally, there were to be 32 DDG-1000s. It kept getting cut to, finally, 7, then 3, and now none of the 3 will have 57mms. So, the Mk.110 requirement went from 64 to Zero…

    The LCS was originally a 55-ship program, and it has been cut to a maximum of 32. So the requirement for number of systems has fallen here from 55 to a max of 32.

    The WMSL was going to be 9-ships, but 8 was probably always the best case scenario. With seven for sure, this cutter program looks to be the most-successful design of the three programs.

    By my count, the Mk.110 requirement (and original development cost planning) was based on around 127 systems. Now, it looks like, the true number is closer to 40. At what point does the 57mm gun program not look financially supportable? Even with adding 25 OPCs, the total number of systems in inventory will be half the original planning projections. I know the gun is supported overseas as well, but if I recall, there was a US production line set up in KY or TN just to build the US guns. I’m thinking the per-gun cost is going to rise steeply, as is the ammunition cost due to lower volume of use with half the projected systems.

  6. It has to be top weight. Big hull. Modern design methods. And still a cock-up. Not good.

    I want to see them at sea purely out of interest, but I think their time in service will be short.

    How is the USN quest for a cheap frigate/LCS replacement going?

      • I like the Bertholfs; they are a Rolls Royce solution for its paramilitary, law enforcement, and rescue rolls. It may be a starting point for a frigate but off-the-shelf the design is surprisingly specialised and very much a product of the US’s depth of capability, but it certainly isn’t the starting point for what the USN needs in a LCS or cheap frigate. I would humbly suggest as somebody who doesn’t have the faintest inkling of what they are on about what the USN needs is a hull with 2 x 5in for PGM, flight deck and hangar capacity for two Sea Hawks plus space for UAV, a second battery of auto-cannon (both RWS and manned) to cover all arcs, and perhaps to reduce costs and interference with upper deck layout diesels instead of gas turbines. All of that should be possible in 6,500 tons, 460ft length, 65ft beam, and a draught of about what 20ft or less. But I am clueless.

  7. Why would the Navy delay the release of their findings/decision on SSC? Is this move designed to mute industry push-back?

    • Think the best, maybe they are still “staffing it” but yes I think this is intended to minimize the usual second guessing and lobbying. For every winner their are certain to be several whining losers.

  8. Anyone have reliable ammunition cost information for the Mk110 and Mk46? I saw some insane figures for the 57mm rounds that had to be early low rate numbers (or just plain wrong) because if true, then half the cost of an operational Mk110 would have been one set of fully loaded magazines. Given the larger number of systems that use the Mk44 Bushmaster, the Mk46 should have the advantage of a larger and more stable business base for ammunition.

    IMO: Bill Smith hit the mark – plummeting quantities spike the estimated unit cost for future procurement and sustainment (the Nunn-McCurdy acquisition death spiral). Top weight may also be an issue, thanks to the move away from the composite deckhouse, but it is usually safe to bet on cost as the deciding factor.

    • The only things I could find relatively easily, Pete, was a contract with BAE from 2011 for a mix of target practice and the 3P rounds. It averaged a little over $4300.00 per round of ammo, but I’m sure the TP is much cheaper per round than the 3P with its pre-fragmented case and programmable fuze. There were a couple contracts between 2006 and 2011, but I didn’t find reliable cost-per-round data.

      Interestingly, before 2006, the US “borrowed” ammo from NATO allies (Norway, I’m sure). I’m not sure how one “borrows” something which is expendable and then uses it, but my guess is Norway wrote it off as economic support of one of their industries…

      I did find that DOD is soliciting right now for interested parties who would be interested in getting in on bidding for manufacture of this ammo. That makes me think, they recognize there is a cost issue, and they think competitive bidding might lower those costs. I hope so, but we also must recognize that IM munitions are going to be more costly due to development costs and the inclusion of stabilization materials.

      • If they are just now considering cost an issue, where have they been? $4300 a round is just stupid and profiteering. I can understand the supply and demand principles. During the war of 1812 the Ames Foundry upped prices for 6-pounder solid shot from fifty cents each to six dollars each and there was no guarantee they were correctly sized.

        It may be time to look into reopening government run ammunition plants.

  9. Cost was the reason Alexander Hamilton did not put cannon aboard the first cutters. He probably would have forgone small arms had they not been a free issue from the West Point Arsenal. Not much changes in the Coast Guard.

  10. Haven’t there been complaints from the GAO and others about the performance of the 57mm on the LCS? Could that have something to do with the switch on the Zumwalt?

    • I think the complaint was that it was not good for surface fire support, and the question was couldn’t they use 76mm. (Not that the 76mm is all that good for fire support.)

      • I saw a video of one of the test, probably the OPEVAL and they had problems with both the 57mm and the 30mm guns. The post you referenced said, “In particular, the report says that the LCS Freedom variant’s 57mm and both 30mm guns revealed performance, reliability and operator training deficiencies.”

      • I have no experience with the 57mm, but the feedback we have gotten on the blog seems to indicate that it is easier to maintain than the 76mm on the 378s and 270s. The LCS manning is very thin. I would guess that is part of the problem.

        Any additional comments, particularly from those with first hand experience are welcome.

      • I should have said how dose the 57 on the NSC compare to the 57 on the LCS. that probably makes more sense.

  11. Here is a quote from a recent Navy times story on the DDG1000, http://www.defensenews.com/interactive/article/20140928/DEFREG02/309280017/Meet-Zumwalt-US-Navy-s-Stealth-Destroyer-Will-Go-Sea-Next-Spring
    “But Downey (program manager–Chuck) also saw the Mark 46 30mm gun, in use aboard San Antonio-class amphibious ships, as a contender for DDG 1000. The smaller gun, he said, “was half the weight, half the cost, and had more offensive combat capability” than the 57mm. “I asked the team to go back and relook at the gun issue.”

    “The analysis, he said, showed that the capability of the 57mm “was overstated in the model,” while the 30mm was understated. “They saw a system that did not meet the requirement anymore and one that did.”

    “A bonus, he pointed out, was a reduction of 24 tons by using the 30mm guns.”

    I still have my doubts, but the 30mm might be a good system for Cutter X (https://chuckhillscgblog.net/2014/09/28/cutter-x-revisited/).

    • For a forward deployed Cutter X or small naval patrol boat I would like something like this.

      30 mm forward
      25 mm aft
      2 mk 60 box sea griffin launchers
      1 SeaRam
      1 Mk 32 LW torpedo launcher
      4 manned 50 cal mounts

      • Some thoughts on your recommended outfit. Assuming you are looking at an environment like that faced by the 110s and Navy PCs based in Bahrain, generally it looks good.

        I would be hesitant to recommend two guns of different calibers that are as close as 25 and 30 mm, but there is an easy fix in this case. The Mk38 mod2 can also take the same 30mm gun as found in the Mk46 mount so that they could share ammunition. There is also a Mk38 mod3 mount coming that will mount both a 30mm and a co-axial .50 cal. machine gun, that could replace both the Mk46 and the Mk38 mod2. http://www.defensemedianetwork.com/stories/bae-systems-developing-next-generation-mk-38-gun-mount/

        I like the SeaRAM because it can automatically engage multiple incoming ASCMs.

        Since the US (at least as far as I know) still does not have a light weight torpedo that is usable against a surface vessel, the torpedo tubes would only be useful if the vessels were equipped with sonar. Seems the Europeans, Russians, and Chinese all have ASW torpedoes that are usable against surface ships, but not the US.

  12. I was thinking of the torpedos for ASuW, because if you start putting on ASW capability, then you’re kind of in a whole different class. I thought I had read somewhere that some of the later Mk46 torpedos had ASuW capability, but apparently that’s not the case. Not sure if they could be modified or not. Maybe the antitorpedo torpedo or a foreign model would be an option if not. But now you’re talking money, so maybe it wouldn’t work.

    On the original topic of the switch to the 30mm on the Zumwalt, hard to tell if it was just a cost and weight thing and they’re trying to put a positive spin on it, or maybe there are more issues with the 57mm than we’ve been told.

    • The switch from 57mm to 30mm really does look like an attempt to put the best face on an unfortunately necessary compromise. If not, then the Navy has really screwed up in the way they have armed the LCS and the NSCs. Even if the 57mm performs as advertised, I have always felt it was a bad choice for the Coast Guard ‘s mission set, since our vessels are much more likely to engage a ship or do Naval Surface Fire Support (NSFS) (in a relatively benign environment), rather than engage hostile air contacts or confront a swarm of small boats. https://chuckhillscgblog.net/2012/11/19/case-for-the-five-inch-gun/

      I have seen documentation that indicated the Navy intended to modify their light weight torpedoes to have an anti-surface capability so they could be be used by unmanned surface vessels.

      It should not be much of a problem to reprogram obsolete ASW torpedoes to make them effective anti-surface torpedoes, but their may not be any available. I understand that Mk46 torpedoes are being converted to Mk54s.

      For our purposes, a relatively simple torpedo, not much more sophisticated than the acoustic homing torpedoes of WWII would work. Tesla could probably make the propulsion system out of parts off their shelves. The sensor and software would probably be a subset of an existing system.

      If there is a major war, with a near peer opponent, I would expect that our new cutters will at some point be given an ASW role. Probably in the form of a towed array and ASW equipped helicopters.

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  16. First test of the 30mm on the Zumwalt. This comment strikes me as a bit strange, ” The test firing on board Zumwalt was the first large caliber weapons firing event for the Zumwalt Class Destroyer Program ” since the there is no way the 30mm should be considered a large caliber weapon. It is no big deal because this weapon has been in the fleet for almost 15 years. Since the 155 mm guns, which would have been large caliber and were central to the design of these ships, has proven a stupendous failure, it ought to be an embarrassment to even bring this up in public. I really hate to see the Navy screw up so badly. https://www.navalnews.com/naval-news/2020/05/uss-zumwalt-test-fires-its-30mm-mark-46-mod-2-gun-weapon-system-for-the-1st-time/

    • To be fair, the stupendous failure was not the weapon’s, but the Navy’s failure to foresee the associated costs to economies of scale when reducing the weapon acquisition by 90%. The Navy could have mitigated this earlier by developing more than a single ammunition type for the damn gun (like every other damn gun the Navy fields) and by expanding fielding possibilities once the ship reduction was decided. They could have fielded the Advanced Gun System-Lite (AGS-L) on the Burke Flight IIA: Restart, Flight IIA: Technology Insertion, or Flight III.
      or, even by committing to field the AGS on the Future Surface Combatant.

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