If I remember correctly, post-war, delay coils were provided to the center guns. This means there was a slightly delay between firing the outer guns and the inner guns(I assume). In-war however they were probably about as reliable as most quads.
That specific photo is of Jean Bart, so she has most deffinately gotten the problem solved, since she was completed post-war.
For more info on the gun:http://navweaps.com/Weapons/WNFR_15-45_m1935.htm