Hey guys, I just want to re-iterate some things we can already assume through video footage of the Machinist...

First, it appears Attachments are ability oriented attacks and they are temporary abilities. Footage has shown the the Machinist load an attachment and the fire an attack powered up by that attachment. We can assume, then, that the Attachments are temporary buffs or abilities that either grant existing attacks an additional effect or that they unlock/grant access to certain abilities when an attachment is used.

Another way to put it, think of the Ninja poisons and how they affect the ability Mug. Now think of the attachment as an additional effect that changes the effect of that one shot. In this sense the Attachment could be an OGCD ability with a shared cooldown with other Attachments, and players would need to pick the right Attachment for the right ability. Maybe one attachment adds a DOT effect, another could apply an Area Effect attack, and other attachments could be debuffs similar to Virus, Dragon Kick, or Rage of Halone.

Just some thoughts.