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.