Board Thread:General Discussion/@comment-26344910-20150714004740/@comment-25864802-20150806021427

KAPompom wrote: I think it might be a harpoon gun. Garnet's gauntlets as the slide and the pinky finger as the trigger. Pearl's spear as the hook part and Amethyst's whip as the chord.

It also has :

Strength from Garnet's gauntlets

Long Range from Amethyst's whip

Precision from Pearl's spear

That is the most plausible.