DefenseNews reports on the controversial decision to replace the planned installation of the 57mm Mk110 on the DDG-1000s with the smaller, lighter 30mm Mk46. The remarks by the project manager in d…chuckhillscgblog.net
The original DefenseNews article seems to be gone, but the above site quotes from that original article where the DDG-1000 program manager defended the switch from the 57 mm Bofors to the 30 mm Mk46 because their real-world evaluations found the 57 mm Bofor's lethality to be significantly overstated. This was from 2014. Has this been refuted since then? I'd have to think so since the US Navy itself required the 57 mm Bofors be fitted on the just selected FFG(X) and the RN has the 57 mm Bofors on the upcoming Type 31. There also doesn't seem to be reports of complaints from other 57 mm Bofors operators. If the original US Navy testing was based on the 57 mm Bofors on the LCS, maybe it's just an LCS related issue since for example I believe the 57 mm Bofors is not integrated into the radar or CMS on the LCS and just uses independent EO fire control.
I remember the quote at the time and while I don't have any hard evidence to bring to the table, I can't for the life of me see how a 57mm round *wouldn't* be more lethal than a 30mm round - the difference in payload is pretty significant and as you say, there are two initiatives underway to provide cheap (or at least, more affordable) guided rounds for the 57mm,
The 57mm looks to be a pretty useful addition to the RN and frankly, I'd be sticking a few more on various hulls if budget permitted.
Something at the back of my mind tells me the RN already committed to one of the two guided rounds and has budgeted for this already - I'll see if I can find the article.
My suspicion on the DDG switch is they just had a top weight issue and wanted to shed a few kg's.