I'd consider making the 3/70 be the same gun with a different (lighter, more reliable) loading scheme. A single barrel on a lousy gun platform isn't going to be a fantastic AA weapon regardless of ROF, and one would certainly rather have 50rpm every day than 100rpm two out of three. Meanwhile, you're already building a new mount around the weapon and I can't think of any other application where you'd use anything but the twin. So again, you'd end up with something like the forward half of USS Asheville. Hell, you could do worse than using exactly the US 3/50 mount.
What about the US Mk63? That might be ok (if the UK can stand the extra dollar expenditure!).
Thanks again chaps. I was aware of the lack of a FCR and something approximating the GUNNAR set; but it would have to be 'home grown' I'm afraid, or maybe licence built (US Dollars
). And I don't think the RCN used that system on the British 3/70 dual mount. With the actual mount I'm sticking to the AU being one that has new systems introduced. My reasoning behind a 'single tube' 3/70 is that it would fill a niche, where the much heavier twin mount would not fit. There has been much debate on the actual 3/70 twin in RN and RCN service, and as a working practice I take the side that it was an o.k. mount. Looking at the actual below decks loading on that mount it would seem that a simplified single would work; all that would be missing would be the FCR, so that must be included now. I should also mention that both the new gun mounts: the single 3/70 and the dual 40mm enclosed will be further developed into fully automatic systems for the next generation of warships. I'm also waiting for someone to query having an all new 40mm twin as well as Seacat? Seeing as how Seacat was adopted to fill the same niche; but again in this AU both evolved an overlapped in some applications