All tests done w/ same gear (15% range alacrity) mouse button was held down when fusilade was used and stopped on first reload. (number is how many bolts used so shots assuming bolt consumption is 1 for 1 regular conjured bolts used)
Heavy Repeater
86
84
85
Gxbow
81
84
78
So it seems that at least in fusilade, gxbow is the way to go without a doubt on an arti, not applied would also be the extra doubleshot, crit range, and damage that the gxbow gets which would increase its dps even more. However im curious as to how stuff like snipershot would play into these calculations as the repeater would get 3 shots compared to the gxbows 1 if someone whos good at math could help out there, at least on pure arti or non sniper shot/aimed shot arti builds gxbows are better in fusilade.