I think the .223 is just fine for a deer, but like with any caliber its about placement, My brother in law is a game warden, and he told me all the poachers use is 22lr and 22wmr guns becuase they are quiet, and will kill. so if a .22lr is enough for a whitetail doe and the .22wmr is enough for a buck a .223 sure as heck is. will a .223 drop a deer in its tracks? occasionally, wil a 150gr .308? occasionally? how about a 400gr arrow? occasionally, basically its the shot not the bullet, a bad shot with a .308 isnt any better or worse than a bad shot with a .223. just watch all those hunting shows that run 24/7 maybe every 10th deer drops in its tracks regardless of what is used.
As far as the round for .223 hunting i would use a softpoint, not a vmax just a lead nose, i cant remember who in the post said it but the vmax poly tip rouds do tend to "splash" on the surface great for varmint hunting or home defense. but i wouldnt go for a deer with one. My 1-9 twist Bushmaster will shoot 69gr ammo all day ive gone out to 650yds with it, but my heavy pull factory trigger and 16" barrel starts to let me down, honestly its kinds squiffy at 500yds in wind with that 16" barrel