The War Zone provides a video of one minute and 36 seconds of a RIMPAC2024 SINKEX.

The firing platform is an Air Force AC-130J and the weapons used were a 105mm (4.1″) howitzer and a 30mm chain gun.

As noted previously, to respond to a terrorist threat, the Coast Guard needs to be able to forcibly stop any ship, regardless of size. I don’t think the weapons the Coast Guard has can do that. So, I wanted you to see the effects of the weapons used in the video.

We already know that 30mm rounds, weighing about twice as much as the 25mm rounds, are much more effective. In a US Navy test against boats (65 feet long or smaller), the 30mm did nine times the damage to the hull and five times the damage inside the hull. The 25mm rounds, exploding on impact, failed to even penetrate the 1/4 inch aluminum hull of the Mk3 target boat.

Against larger targets, is even the 30mm gun used in the new Mk38 Mod4 effective? It appears the rounds may be exploding on impact. You would not want to be out on deck when this happening, but it appears the rounds may be exploding on contact and not penetrating.

The 57mm round is about 7 times larger than the 30mm, but still relatively small for a naval gun.

You see a hit from the 105mm at 30 seconds. The 105mm fires a 33 pound projectile, about 5 and a half times larger than the 57mm. It would have probably killed anyone in the bridge, but even it did relatively little damage to the structural integrity of the ship. It did not seem that any of the damage effected the engineering plant or the watertight integrity of the ship.

Getting a mobility kill on a ship with gun fire is extremely difficult. What the Coast Guard has is not what it needs.

More here, here, and here.