RFB deck gun a against surface fleet I sank 100,000 tons in 10 minutes with RFB, including unaltered RFB target and sub damage models. So I kinda think you can hit a few targets with the RFB gun.
This was to make fun of all the players who brag about tonnage scores. Not many hang out here, but Ubi forums has lots. One guy bragged about coming back with a 100,000 ton cruise and I said "no big deal, I did it in 10 minutes of real playing time." He accused me of bragging so I released the tools so EVERYBODY can do it. I'm far from the greatest captain. Maybe most would do better than I did.