If it's only the AP shells you can't spot, you aren't using the correct HE shells.
LHE and AP have the exact same range. If you can't spot 1, you shouldn't spot the other.
Using normal HE or heavy HE shells on a BB is an absolute nono, range is everything for BB's.
Use LHE in the 1st locker, AP in 2nd. Mixing ammo ( some guns firing LHE, some AP in the same salvo) is not the smart thing to do.