I love lights on guns. My credo is: Pistols, rifles and shotguns, if they stand any chance of being used defensibly, should have a light mounted on them. Period.
Do NOT fire 5.56 NATO in a .223 Chamber... That being said...
This is a long debated issue that keeps getting brought to the forefront as the AR platform becomes more and more popular. I will break it all down for you, but I will hit the most important highlight first.
Kimber sought out to make the perfect micro compact pistol that would be reliable, accurate, durable and fire +p ammunition. They easily achieved one out the four goals it fires +p ammunition.