Talk:38cm Quadruple Gun Mount Kai/@comment-32095214-20170813043056/@comment-30534142-20170813123239

With pleasure =) :

 As designed, Richelieu's guns had a muzzle velocity of 830m/s and a max range of 41.7 km at 35° elevation, on par with the Littorio class, but  the close proximity of the barrels of her guns caused vibrations which gave her dispersion issues (same problem than some Italian and US cruisers). Those vibrations are also partly responsible of the explosion of one of her gun during the Battle of Dakar by the way.

 After her very first baptism of fire during the Battle of Dakar, the issues of her guns and shells were discovered and changes had been made to try to improve them such as reducing the charges to improve accuracy (it is worth to know that at that moment, Richelieu was still incomplete and several of her systems and equipments were barely functional since she had to escape France hastily under fire to avoid capture).

Those changes and fixes had been carried out during her refit in the US in 1943, and she had been issued US shells. Thus she now fired shells at 785m/s and her max range dropped to 37.5 km at 35° elevation (similar to most US BBs). With those changes, radars and new firing doctrines her accuracy improved but the issue of the vibrations was only resolved post-war in 1948 by adding delay coils on the center guns. With those her average dispersion was 300 meters at 26.5 km  http://www.navweaps.com/Weapons/WNFR_15-45_m1935.php

Hope it helped ^_^