All guns are usable, you're using Red Death, lots of people use SUROS, I like Thorn and Up For Anything. One gun being flat out better than another is part of all these games. Otherwise you could have kept your first gun from PVE and ran with it the whole time. Even Halo, a lot fewer people used the battle rifle once the DMR was available because it did more damage per shot. It didn't make the BR useless.