223/5.56NATO

Question
I have a Ruger mini-14 in 223 Rem. and have heard many different opinions on whether it is safe to shoot 5.56 NATO in this rifle. Would like to get your views on this.
                               Thank You

Answer
The .223 caliber ammo and 5.56 Nato round are so similar that they are often mistaken as both being the same size ammo. The 5.56 round was designed for military rifles with a different throat configuration than that of sporting rifles. As such, the .223 is rated for a MAXIMUM of 50,000 CUP. The 5.56 round has a CUP of 60,000, which is 10,000 extra which is sufficient to cause a failure in the barrel and chamber of the .223 rifle. In short, you can fire 5.56 Nato ammo from your .223, however each shot you take with it will be a gamble as to when the barrel explodes in your face, likely causing you to go blind and disfigure your face at best.