Talk:Type 91 Armor-Piercing (AP) Shell/@comment-3213090-20150501062538/@comment-175.156.25.196-20150502062646

From the http://kancolle.wikia.com/wiki/Artillery_Spotting

Artillery Spotting (DA & CI) cannot miss, but may scratch the target due to weak shelling power and/or low accuracy. Scratching will inflict ~10% of the target's current HP as damage.

Double 41cm will actually result in a small accuracy penalty on FBB if I'm not mistaken. I would recommend putting a maximum of 1 41cm and 1 36.5cm. You might deal less damage on a whole, but at least you will hit more often.