The 6.1N and 6.1D are the only IJN guns that block. Although they won't block at level.
And blocking trip 6's aren't so interesting.

you get to use them once you're using an Agano CL, they're nice. but 4 seconds to
reload :(

what the hevk is that pics..heheh

yes angus was right i believe

As for the guns, what ship are you using?

It could also be your gunners, not classed as...heavy gunners I think.

Yes, your gunners should be able to use those guns, however it is likely that you do not
have the necessary gun space on your boat. The D version require 100 gun space to
mount, even without ammo. Where as the L require 114 space.

What boat are you trying to mount the triples on?

On a side note, please don't type in all capital letters.