As a newbie, I have yet to use chain shot, but have used grapeshot in support of boarding actions. We haven't used the carronades rule yet, so I will bring that up at our game in 2 weeks and see if we want to try it out.

I just finished reading "Ships of Oak, Guns of Iron" by Ronald D. Utt which is about the War of 1812 and an excellent book. An interesting point he brought up was the use of double shot in carronades and their general ineffectiveness. The extra ball reduced the effectiveness of the smaller powder charge used in the carronades and the double shot often failed to penetrate the scantlings of the target ships, often lodging in the scantlings themselves or bouncing off (see page 256). Something to think about!