http://www.youtube.com/watch?v=QINwCaJgX4o
For those of you who have seen this video, place-able Machine Guns will be in 1.0.
This idea seems thought out and well inserted, but I think for the sake of realism (well, a bit of realism) that turrets users should have a limited field of view in which they can turn their turret. This makes it whereas the turret isn't a camping weapon that be placed in a slightly protected area and a player can rack kills easily. Also, I think the turret should not have an infinite amount of ammo. Being its nature, 200 - 450 bullets sounds reasonable for the turret.
That is all, please share your thought and criticism.