It's a slightly weird description for the repeating Arquebus, it honestly seems a bit quick to reload. For damage I would use the 2D6 of a normal Arquebus. So I guess if it hits there is no real need to roll damage (2D6x108) I would maybe give it an area/cone of effect rule. Honestly it seems way to strong unless the Party is in a Leviathan.
As for the repeating Musket maybe it's based on this,
https://en.wikipedia.org/wiki/Kalthoff_repeater#:~:text=The Kalthoff repeater was a,weapons following the Kalthoff design.
I would go for the smaller ammunition load and it being very rare and expensive. Though from whats in the book it seems almost like a Puckle gun in that it needs to be set up so? Again I would keep the damage the same as the single shot weapon, you just get to fire it longer without reloading, I also might think about making it an Advanced skill like Polearms to reflect using such cutting edge weaponry.