Being a new guy here, I can't find a quote button, but this is for Wrenches. Really you don't need to separate your brass by 223 vs 5.56x45. Unless your loading MAX loads, either brass will work in either a .223 or 5.56x45 rifle. The major difference between these 2 specs is the 5.56x45 has thicker walled brass. Which will reduces the inside capacity of the round. Meaning if you load near max loads in .223, in a 5.56x45 round will equal a +1.0 grains of powder in capacity and could easily put you over the max load for that powder and brass. This will cause a Ka-Boom.