I'll have to keep that in mind about the witch.
I'm finding that I'm using dual pistols more and more. It has a bit of a slower reload, but it is super powerful and if you hit the trigger fast enough it has a faster firing rate than the m16. Also, when you're being swarmed I found if you hit reload, and then start melee'ing, you'll still be reloading and after a few melee hits you'll be good to start shooting again.
Pistols are also accurate enough, when crouched, to get headshots at a distance.
Using dual pistols I find I'm topping the most killed charts quite often.
When a hoard is rushing you, just aim for head level, and spam that trigger. On smaller groups I'm able to wipe them out before they even get to us. Its crazy. If a few get through then beat them to the ground.
The hunting rifle is good for clearing groups too. The rounds can pass through multiple targets in a line at once. So when when in a corridor and a hoard is rushing you they'll be so clumped up that you just have to put a few rounds into it and you'll probably kill most of them.
There is no more satisfying feeling than when a hunter tries to pounce you, or anyone, but you react first and melee it then proceed to keep beating on him until it is dead without it ever having hit you once. Stupid hunter. I did the same to a smoker once. That was nice too.