well if they arent meant to use the cartridge like a projectile it will just be similar to FF8 gunblade as means of adding OMPH to you strikes by turning the blade into a high frequency blade
I wonder which one of these gun blades could be a legit weapon?
The one on the bottom right (which I presume isn't a gunblade at all) is the only one that doesn't look like it would snap in half if you struck anything with it, and that is the one that is too badly damaged to be worth anything more than a metal club.