From seeing a bunch of these penetration tests, it's hard to tell exactly what a 223 round will or won't go through. It seems very dependent on bullet shape, weight and construction.
One thing that seems to be a constant is that a 'classic' 223/5.56 (~55gr or so) will generally penetrate drywall less than most handgun or shotgun rounds.
That actually makes sense too. Force = Mass times Velocity SQUARED. So if you start reducing the velocity you are reducing the force by a much larger amount than if you reduce mass by say, fragmentation.
Going through drywall may not break up a 55gr FMJ round, but it will definitely cut it's speed by a good chunk. And as they say, speed kills.
One thing that seems to be a constant is that a 'classic' 223/5.56 (~55gr or so) will generally penetrate drywall less than most handgun or shotgun rounds.
That actually makes sense too. Force = Mass times Velocity SQUARED. So if you start reducing the velocity you are reducing the force by a much larger amount than if you reduce mass by say, fragmentation.
Going through drywall may not break up a 55gr FMJ round, but it will definitely cut it's speed by a good chunk. And as they say, speed kills.