Gunnery.

[Diamondback]

Spot on! This was true of all these multi barrelled guns Dave.

The seven barrelled gun weilded by Harper fired all barrels in quick succession and consequently had a kick like a Mule, plus if your man went down having started the sequence the gun woul spin around on the floor or deck continuing to discharge, and indiscriminately hitting friend or foe alike. This is the main reason that the Navy discontinued its use as a boarding weapon.

Rob.

Sounds like the Harper gun would have been better employed as a shipboard fixed-mount for suppression fire while the boarding team made their approach. Technology only carries you so far if you don't develop Doctrine to effectively employ it... I believe the modern buzzword is "Failure of Imagination."

[Bligh]

Sounds about right to me DB. I can imagine the old shellbacks saying, why would we need tha when we have swivle guns which acomplish the same thing and expell more shot.
During my research into the history of firearms the one thing which came through loud and clear was the resistance of the Horse Guards and the Admiralty to any new innovations. This was also true of foreign Powers at the time, and continued certainly up to the First World War within many departments of the War Office. I do not have enough knowledge to comment on later periods but could hazzard a guess.

Rob.