It's a lot of camping and team shooting. This gun will simply not outgun anyone that's half decent, I got my done in rift and just tried to make sure I was always in a position where I could get the first shot off, or just piggyback a kill off of a teammate. If you're a hunter I'd recommend grabbing a Tripmine and some throwing knives so you can hit them with one of those and tap them once in the head for the kill. If you're a striker try out lightning grenades, or try axion bolt grenades on a warlock. You're not looking to kill people with your grenade, just get them to a point where 1 headshot will kill them. Doing these I completed the bounty twice, first time on my 4th game and second time on my first game. It's not that difficult just requires a change in strategy.