I agree with Helmic.
While I understand the flèchette ammo I don(t see it as a problem that should prevent the Carronade from being enjoyable to shoot with.
Altough my choice of pic may not be the best I have to admit I did not find a good one with a true Carronade firing. But you get the idea. Something impressive, one way or another, should comes out of the carronade. When you fire flèchette rounds with a regular shotgun it is still loud and have recoil. A gigantic twin shotgun, no matter the ammo, should have a nice animation and sound to go with.
And even without this, it is a game where immersion nd visual feelings are important so I would really appreciate to have a little sound and visual change on this fantastic weapon.