So I bought a bushmaster M4 this week. The receiver says .223-5.56, the barrel only says 5.56. I was told that I can shoot both rounds through this. Is this the case? I would like to know if I can shoot .223 as well.
.223 is safe to use with a 5.56mm chamber. The opposite is usually true, but technically speaking you shouldn't use 5.56mm in a .223 as 5.56 chamber specs run a little larger in some areas and chamber pressure is higher with 5.56.
