I've been meaning to mention that the stacked or superposed loading concept has been around since at least the 16th century.
http://en.wikipedia.org/wiki/Superposed_load
It's not directly mentioned in the above link, but I remember seeing plans for a early 18th century volley gun with 50 barrels each loaded with twenty rounds. What caught my attention was the triggers set near the end of the barrel. I remember it used special fused bullets that passed the explosion through to the next bullets powder charge so it could be touched off only in groups of twenty shots per trigger pull.
howard melton
God Bless
http://en.wikipedia.org/wiki/Superposed_load
It's not directly mentioned in the above link, but I remember seeing plans for a early 18th century volley gun with 50 barrels each loaded with twenty rounds. What caught my attention was the triggers set near the end of the barrel. I remember it used special fused bullets that passed the explosion through to the next bullets powder charge so it could be touched off only in groups of twenty shots per trigger pull.
howard melton
God Bless