And it sits smack bang in the middle for the RANs original requirement of 40mm for the Arafura's(12) and 30mm for the Hunters(18) and those requirements could be for up to 40 guns if you throw in the follow up MCM/Hydro ships as well. Certainly plenty of advantages going with a single calibre unless the RAN decides to go all the way to 57mm.
Add in the potential to replace Typhoon mountings with 25 mm Bushmasters provided the mounting area can support the increased mass and that number expands even further across the fleet. If the electronics, sensors and CMS of the RAN's amphibs and support vessels can manage it, Millennium Guns could also potentially replace Mk 15 Phalanx as self-defence options for the
Canberra- and
Supply-classes.
If done correctly, a set of single training, logistics, maintenance and support streams could be operated to support current and future RAN small calibre gun needs. IIRC current plans require five different ones to accommodate the different calibre rounds used, the different guns, and the various mountings across the current and as of now planned for fleet. Part of what gets me about this is that the and variety of capabilities the current mix of small calibre guns is IMO rather limited, with only the Mk 15 Phalanx really providing any sort of CIWS capability vs. aerial threats or inbound missiles. Everything else is really only appropriate for use vs. smallcraft. Me being me, I would much rather there be a dual or multi-use gun which can add an additional layer of close-in air defence, rather than only being able to destroy hostile FAC's.
As for the Mk 110 57 mm gun being adopted... the only way that might make any sense (IMO at least) was if the RAN were to decide to start having a third class of MFU start entering RAN service as a GP frigate to both accelerate the replacement of the
ANZAC-class FFH's and over all increase the number of MFU's in RAN service beyond the currently planned for dozen. If (very very big IF) this were to happen, and then the RAN were to select an Australian or Australianized-version of the USN's planned
Constellation-class frigates, then having the design retain the Mk 110 and having a new gun brought into RAN service might make some sense. Otherwise the Mk 110 is really too large to be a small calibre gun, whilst also being rather on the small side for a main naval gun.
Side note: For me, I do see potential value in the RAN adding a third class of major warship into the planned fleet, providing the planning and implementation is done properly. However, unless/until the RAN, ADF, or AusGov provides some sort of indication that the should or will be expanded beyond a dozen majors, I do not wish to encourage 'fantasy fleet' building. If members are interested, I can put forth my ideas on why it
might be a good idea, but I really do not wish to restart any of the, "The RAN should get
NN vessels of
XX-class..."-type discussions.