Do yourself a favor and don't. I am a nub still learning the ropes while i still tested it for a month. I can say i lost every fight i plaid on this rifle warrior in gvg/pvp in 1v1. I had fun being a might dispenser with rifle for the entire gvg team tho, was fun but boring after a while. And going that route makes your dps even lower. There i could "help" making some kills by letting holo/revernant and other meta classes that do 90% of raid dmg while providing better buffing, more survivability like they have entire dps/tank/heal in one class.
Now what i have encountered:
I see mesmers with light armor and lower hp than me that i barely do dmg to them on top of being able to spam illusions and kill me in seconds.
Revernant/guardians they overheal your every burst while staying afk not dodging just using their dps abilities and burst you down instead.
Necros same as with guardians/revernant your bullets just heals them. When they eat enough bullets they enrage with their second hp bar runnin after you while your entire bar is filled with debuffs. They wear light but they as tanky as main tanks in other mmorpgs in this game vs your dps.
Engi you feel you do dmg to them but their mech+ weapon out dps you while they have more aces in their sleeves vs you. If it's scrapper or holo then good luck doing something, anything at all.
Thief while you do dmg to them and feel you gonna win. They there at one point then they are not, gl finding them.
Ranger same as with engi+pet they just overdps you even if they have same surv as you. They have an extra pet that does dmg than you. So they win the fight.
Elementalist, haven't encountered that many in pvp or they were just downed a lot by other people than me to see them. If you have issues with revernant/guardians because their self heal and dps. ele have same kit heal+dps while you have half dps and 0 heal
With my rant over imma delete my rifle warrior. Not gonna touch one even if they improve the melee side of it to be on par with other op classes. xD