A New 30mm Round –Maybe a Reason to Upgrade the Mk38 Mounts

Military.com reports that Northrop Grumman is developing a proximity fuse for the 30mm gun that arms the San Antonio class LPDs and is part of the Surface Warfare module on the Littoral Combat Ship. The new round is being developed for use against drones, which are a difficult target to hit directly. It might also make the gun more effective against the small boat threat and should improve its chances against aircraft.

The Coast Guard also has an interest in being able to down drones, but this may also be of interest to the Coast Guard because it may provide the incentive needed to upgrade the guns used on Mk38 gun mounts, not just in the Coast Guard, but in the Navy as well. We have known for a long time that the 30mm round is much more effective than the 25mm round, but there has been no movement toward replacing the 25mm guns.

The Mk44 Bushmaster II, 30 mm chain gun is a derivative of the 25 mm M242 Bushmaster. They share a number of parts. All indications are that there would be no significant problem in replacing the M242 Bushmaster used in the Mk38 gun mounts with the more effective 30mm gun. The Mk38 gun mount is the primary armament of the 210 foot WMECs and Webber class Fast Response Cutters. It is expected to arm our Offshore Patrol Cutters and replace the 76mm on WMEC 270s that go through a planned Service Life Extension Program.

I really would rather see either the 50mm version of the Bushmaster III or the 40mm version of the Bushmaster II, but while none of these options are a complete answer to the Coast Guard’s need to be able to thwart a potential terrorist attack, any increase in projectile size allows both engagement at greater range and increases the probability of success against larger threats, while maintaining equal or better probability of success against smaller craft. The 30mm would be a significant improvement.

8 thoughts on “A New 30mm Round –Maybe a Reason to Upgrade the Mk38 Mounts

  1. Agreed! The 50×330 would probably be a better choice, and more likely to have Smart Munitions for the gun than anything smaller…

      • Not really the same because this does not dispense its shot shortly after exiting the barrel, it explodes a distance from the gun based on where the target is. It is a proximity round. Those do go back to WWII, but it would be the first time we would have such around for so small a caliber gun. It also sounds like they will project the fragments forward while earlier proximity fuses sent most of its fragments radially.

      • The 30x173mm Shot Grenade Round isn’t new! It was developed in May 2002 by “Alliant Techsystems” or “ATK”. As the 30mm HEAB (High Explosive Air Burst)…

  2. The only trouble is, this round is not a good justification, to purchase/re-equip with new guns and calibers, as the smaller the projectile, the more limited-effect the bursting charge and the lower the payload of sub-projectiles. Now, as a package with several selling points, maybe.

    Also, the Coast Guard hates to pay for “fancy” ammunition (e.g. Bofors 3P ammo for the 57mm). I’m sure the Navy is “interested” in the round, because they are looking for how industry would address a threat drone. Thus, the Navy *loves* to pay for stuff like this…

    Frankly, there are already jamming device which interrupt the drone’s signal, which is probably a more effective way to kill a small drone.

    • The “HEAB” Projectile round is also available in calibers as small as 20mm, or larger in 35mm, 40mm, 57mm, 76.2mm and so on. And ATK which produces “Bushmaster” Autocannon rounds, will probably also be developing it in 40 and 50 Supershot calibers too…

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