if the guns are 18-inch ones then either the turrets are too small or the barrels are drawn too big, here is a quick collection wich might help you to archeve the optimal dimensions for your guns:
the uppermost gun comes from the IJN parts sheet, it's the triple turret from IJN Yamato drawn by Erusia_Force.
the middle one is a kitbash of the former done by me for the AU Yoshino class, based on the real life N°13 IJN battleships project (retaining the same dimensions of the twin mount you can see
here) , it's a twin turret.
Finally, the lowermost of the three is the single turret from HMS Furious, done by Hood for the RN parts sheet.
Pick the one wich corresponds with the armament layout of the Chancellor (i don't know if your guns are triples, twins or singles) and adjust the dimensions around them.