Ok, 2 older beauties I just acquired need some clarification. Item 1 is a Colt HBAR Match/ Target/ Competition AR the receiver is stamped Cal. .223 but the barrel is stamped 5.56 NATO 1/9 HBAR.
The other is a Ruger Mini 14 508 series non/ranch also stamped Cal. .223
I have tried to research some history on these firearms as to the use of 5.56 ammo. The manufactures websites are pretty useless, including trying to talk to Tech Support, and the manuals are vague. I just want to feel comfortable using 5.56 ammo.