I just can't get at this guy. Is there a trick I haven't found yet, or am i just too clumsy with the controls to force him into close combat?
Or do I have to wait for an hour or so until he runs out of ammo for his bloody machine gun?

Take cover until you're close to him. Then activate slow motion to get behind him and unload all the bullets you have into him while he is trying to move to the other side of the room.

Yes, that worked. Thanks.