This is something I never understood. If the rocket does 110% dmg, should she be whipping this rocket out for a shot or two at max machine gun stacks, then tucking it back in for the machine gun, or is it better to just spam machine gun?
Rocket is for poking, chasing, hitting snared targets, team fighting, wave pushing or to get a few quick hits before the enemy is in Machine Gun range.
Machine Gun is for straight DPS, turret taking, dueling and cleaning up (Once you trigger your passive).
Jinx's mediocre Attack Speed makes her Rocket a poor choice for DPS, despite the awesome bonus. Most of the ADC's damage comes from crits over small periods of time, rather than straight up big damage.
The stacks will instantly disapear when Jinx autos with her Rockets once, which is why she tends to stick to Pow-Pow during longer fights. I assume the reason for that is because Riot didnt want her to enjoy both bonuses at once, even if for just a few seconds, and frankly, i agree with that decision.
The only time Rockets are great for DPS is when enemies are entering/leaving combat range of the gatling gun, or if you have Runaan's and a large enough cluster to deal a ton of damage with Rockets+Runaan's.
+10% of AD costing 20 mana per shot, not to mention at the cost of pretty much all of Jinx's innate AS, is a pretty steep cost.
