Frustrated, any suggestions?

So I got an exotic Bounty... (WOO-HOO! SUPER EXCITED!) but, now it requires me to get 500 "Points" in the crucible by killing guardians with void damage. Which wouldn't be too hard if this were my warlock, but its my Titan, so I only can use secondary/heavy weapons and my grenade. as far as I can tell I get 5 points per kill, BUT I also lose 2-3 points per death. And kills using any other damage, count as nothing. So here is my frustration, If I get 7 kills in a row with my primary weapon, and then die... I just lose 2-3 points. so I have to basically hurt my team by not fully participating, because I have to stick to my limits of either shooting people 3 feet in front of me (Shotgun) or not being able to shoot anyone closer than 10 yards (Sniper). If anyone has any tips, I'd welcome them. I'm trying to get a void fusion rifle, but I haven't found one in awhile. I never used them so I had been destroying them all, now this seems like my best option. but of course I can't find any, much less, a good one.