When I look through the internet, I note that the .223 Remington and 5.56 mm NATO are the best in business. Most of the Military cartridges comprise of the thicker walls. The 5.56 NATO is a perfect tool for war, whereas the as a civilian I prefer the .223 Remington. My point is what happens if I try 5.56 NATO in .223 Remington barrel… is anyone having the real time experience?