.223 in a 5.56x45 barrel, accuracy loss?

For those with some AR experience  what kind of accuracy loss would be seen shooting .223 remington bullets in a barrel stamped 5.56x45? The leade on the 5.56 is .162 opposed to the .085 of the .223. Is this extra jump to the rifling when shooting .223 going to give a noticeable amount of inaccuracy for the average shooter?
I would like to have the versatility of the 5.56 barrel to shoot both rounds, but not if I am going to see a noticeable difference. I know the Rock River arms rifles make the .223 Wylde which gives you the best of both worlds, but I have the opportunity at a very good deal on a rifle that is one or the other.