[DiN_BLiX]

This will make all the difference. If its marked caliber 223 then 5.56 should be fine. But if it is chambered specifically in .223 remington, there is a difference

Not exactly, ruger specificly states that the chambers in all non-target model mini-14s are in fact 5.56mm chambers. Although the roll stamp says .223, it is in fact 5.56 so any .223 or 5.56 ammo with function properly and safely. Anything else that is marked .223, refer to the manufacturer