As has been explained above (and repeatedly in other similar threads over the years), most factory .223 Remington chambers are deliberately throated long to prevent possible pressure issues is someone shoots 5.56x45 NATO ammo in their rifle. The manufacturers do this for liability reasons. That said, the official (aka Legal Dept. approved) recommendation from Savage is as follows:

Can I shoot the 5.56x45 NATO ammunition in my 223 Rem? 7.62 X 51 in 308 WIN?

Savage Arms does not recommend the use of any military surplus ammunition. As stated in the owner's manuals, you should only shoot the caliber that is stamped on the side of your barrel.
Do with that information as you see fit.