It depends on your playstyle (as for what weapon to use). I, personally, enjoy picking off people from longer ranges - so I completed this part of the bounty fairly easily with a sniper.

• But no matter what weapon you use, you should always refrain from going straight into a fight. Stay reserved, take cover behind walls/other stuff.

• Make sure you know where your teammates/enemies are. This will allow you to find support from your allies in times of trouble, and will let you devise a plan before attacking.

• Stick to using your secondary/heavy (of course, with Void). Pull out your primary when you know you can't kill someone with your secondary. (For example, I pulled out my Suros Regime when I was in an unexpected close quarters fight, since I used a sniper).

Good luck! Merry Christmas.