depends for me if they are standing or moving and the distance for a neck shot.
I've taken several deer in MS in thick woods that all dropped instantly with a neck shot. They were 75yds or under and not moving, except one that was less then five yds in a galop/trot (all with open sites w/ Marlin.30-30, .45colt Win '94, Marlin .44mag lever and one Ruger Blckhwk .45colt).
mostly I will shoot for vitals in long distant shots with my Ruger M77 .270 or Mosin-Nagant 7.62 X 54R (these have simmons scopes) if they are not moving fast...cause I'm not too good hitting long distant moving targets.
Otherwise, in real thick woods I use shotgun...can't beat it!