03-27-2014, 02:52 AM
.223 chambers MAY exhibit high pressure signs with 5.56 ammo, which is loaded to higher pressures. The 5.56 chamber has significantly more leade than the .223, unless the .223 is a variant cut for long bullets. A .223 AR will often exhibit pressure signs with Black Hills 5.56 77gr ammo, for instance. Across the course shooters often have their ARs throated for longer bullets even than 77 grainers.
You seek escape from pain. We seek the achievement of happiness. You exist for the sake of avoiding punishment. We exist for the sake of earning rewards. Threats will not make us function; fear is not our incentive. It is not death that we wish to avoid, but life that we wish to live. - John Galt