“... around a 155 mm gun with revolutionary rocket-boosted shells...”
Having worked on those rounds, they were a turkey from the get go. There is no mission for a sea based round that can travel 100+ miles. In order to achieve that range, the warhead is so small it’s practically worthless.
And the rocket motor ignition system so complex that it was expected to fail 20% of the time.
The Marines need beach blasters and inshore support; inshore, as in 20 - 40 miles.
There’s noting wrong with the concept of a 155mm high fire rate gun, it’s the compromises to get the 100+ mile distance that crippled it and made it worthless.
One would think some old and new designs could be combined to get the navy a class of true heavy cruisers. Room for current weapons and built for possible future weapons.
As for shore bombardment that could be done with the proven
8 inch gun from WWII. Yeah it is old but it works and was used through the Vietnam era.
The Zumwalt class, ahhh... what were they smoking?
IIRC, the 16”/50 caliber Mark 7 – United States Naval Guns on the Iowa Class BBs were VERY effective in supporting USMC amphibious landings!
An up close view of full 9 gun broadside FRom an Iowa Class BB is a sight, once seen and, more important, FELT, never to be forgotten!
Nowadays, smart bombs do that kind of work.
HST, I always felt that the USN screwed up by mothballing the Iowas! Lovely ships!