I’m confused. The Duguay-Trouin has a very strong AA suite (six Bofors guns and TWENTY oerlikons), equivalent to the Krasny Kavkaz among others, and it’s at 4.7. Yet its sister the Primauguet’s AA suite is borderline nonexistent (six 13.2 mm machine guns) and it’s at 5.0.
A few more points to note is they share the exact same primary and secondary guns and their armour is identical ('cause they’re sister ships, duh).
How haven’t their BRs been swapped yet?
Something something torpedoes, Probably…
But that’s generally how some ships seem to have always been where the ship has an increased in AA is a lower BR compared to the TT counterpart with more main armament or more different weaponry (could also be the floatplane), although there are exceptions were if the AA doesn’t replace armament it has an increased BR EG: the fleet torpedo boat T22 (3.7) & T31 (4.0).
Still could be some daft french tax as the Suffren class cruiser is also this but reversed a Colbert is 5.3 meanwhile the Dupleix is somehow 5.7 (similar to above).
Honestly, the mode is screwed in regards to BR’s as some vessels are just placed in the worst spots with the only question to ask is W-W-Why?
I’d say the Primauguet should be reduced to the same BR as the Duguay-Trouin imo.