The Gemini is nice too but I tend to favor high impact/low RoF models. Force of habit, I suppose. For the sword part I found that a high discipline build works well if you want to run around with the hilt in a normal mode, because you can chuck a grenade to damage a foe and it'll be a guaranteed one hit kill when you melee them. Otherwise you should definitely be playing mayhem clash due to the high spawn rate of heavy ammo.