Firing .223 in a 5.56 rifle is a non-issue, and certainly not prone to "slam-fire." I've had slam fires from shooting .223 handloads in my 5.56 chambered Bushmaster varmint rifle, but that was because they were loaded too hot, not because of the leade.Mando'a wrote:Is "slam fire," still an issue firing .223 from a 5.56 upper?
Whatever you do, do NOT shoot 5.56 ammo in a rifle chambered in .223.